MONG tthe factors which
brought about the defeat of the
German Air Force in the Battle

of Britain in 1940 was the highly or-
ganized and very efficient system of
communication for air information
and command. That system permitted
the pursuit squadrons to operate from
“ground alert”? — that is, to remain
in readiness on the ground and take
the air against definitely located
targets only. From the standpoint of
delivering a blow where it was needed,
the system gave to one plane on
ground alert the effectiveness of 16
planes cruising about “on patrol.” It

also made possible the giving of air
raid warnings to the civilian popula-
tion in time for them to take neces-
sary precautions.

A similar system developed by the
Army with the codperation of the
Bell System has recently received ex-
tensive tests in air defense maneuvers
extending along our northern Atlantic
Coast. Describing this system and its
operation, a statement of the First
Air Force said:

“Forty thousand or more civilian
observers are watching the skies for
‘hostile’ bombers and reporting their
courses to some three thousand other

Fig. 1—Civilian Air Raid Warning Board in foreground;
beyond are the test and patch boards

volunteer civilian plotters who are at
work in the filter and information
centers in Boston, Philadelphia, New
York, Baltimore, Harrisburg and Nor-
folk, where operations to combat the
‘enemy’ with pursuit ships and anti-
aircraft fire are directed by the
ground and air commands.

“The men and women of the Air-
craft Warning Service who are par-
ticipating in this unprecedented battle
drill of the air are stationed at
1800 observation posts. They
may be on mountain peaks or
on skyscrapers. They may be
deep in the country or on
rocky headlands facing the
sea. All are in direct com-
munication with the filter and
information centers.

“This all-embracing net-
work is made possible by the
country’s highly developed
telephone system, unparalleled
abroad. It leaves scarcely any
area of the skies unwatched.
And a constant check on the

accuracy of any given
observer’s information
is made by the reports
of the other observers
who are stationed
along any paths the
‘invader’s’ planes may
take.

“When a civilian ob-
server sees a plane he
notes these things: its
type (whether, say, it
is a single, bi-, or
multi-motored air-
plane), the compass
direction in which it is
flying, and insofar as
possible, its altitude.
This information is im-
mediately phoned to
the filter center, where
most effective use is made of it.

“The filter center contains a very
large table map of the area, marked
into squares. These squares are identi-
fied by words and numbers—so that
arrow markers representing the planes
may instantly be placed in the locali-
ties where the civilian observers have
reported them.

arrows grows, and standards bearing
the growing amount of information
about their type, number, and altitude
are added by the civilian volunteers
who have been trained for their work.

“The filter center, true to its name,
filters out erroneous judgments. The
weighed evidence on the enemy’s
course and numbers is transferred to
the information center in the next
room, where on a similar but even
larger map of the region his course is
shown. A ‘status’ board shows what
steps are being taken by defending
aircraft, where they are, in action or
in readiness, and, if they are in the air,
how long they have been there and
the state of their fuel supply.

“Above the status board and the
table map of the region there are
glass-enclosed galleries. Here, officers
in communication with the defending
fighter squadrons, the searchlight and
anti-aircraft batteries and the balloon
barrages swiftly take the measures
that are called for.

“Interceptor planes from the fields
nearest the area where the ‘invaders’
have been sighted are ordered into
the air. Their navigation is plotted
by officers in separate rooms at the
information center, and sent by radio,
so that they know exactly where to
go to meet the enemy.

“Meantime, the Civilian Air Raid
Warning Officer, who is also stationed
in the gallery, alerts the civilian air
raid wardens in areas threatened by
the invading planes, and the organiza-
tions there go into action.”

Development of the present air
raid communication system began
with one set up by various Telephone
Companies in codperation with the
Army during maneuvers, using stand-
ard telephone equipment and circuits.
Improvements suggested by those ex-
periences were incorporated in larger

systems set up by the New York and
the New England Companies, in New
York City and Boston, respectively.
So promising were the results and so
necessary did a nation-wide system
seem that the Laboratories were re-

Fig. 3—Officers in the balcony reach various
points through 101-type Key Equipments

quested to proceed with development
of the telephone portion of the system.

In planning the telephone facilities
for the First Interceptor Command,
the conditions were that quick inter-
communication be afforded; that a
minimum of costly circuits be tied up;
and that standard telephone equip-
ment and circuits be used as far as
possible. It was contemplated that
the Signal Corps would secure the
facilities from the Bell System and
that regular commercial rates for ex-
change and toll service would apply.

set up, from any one of which reports
would be infrequent. A permanent
wire network would be costly, and
would tie up toll facilities which
might better be left available for
public use. Accordingly, reports are
transmitted over regular exchange
service facilities to a nearby central
office. Assume that this observer is
on a hilltop back of Poughkeepsie.
When he has anything to report, he
says to his local operator ‘“Army-
Flash-Hickory.” Operators—local and
toll—who may receive such a call
have been instructed that such a call
is to be given preference, and com-
pleted to any one of a group of jacks
in the New York Long Distance
board marked “Hickory.” From these
jacks a group of toll terminal lines ex-
tends to the Information Center and
terminate on subscribers’ key equip-
ment mounted just below the edge of
the “filter” map, adjacent to the
area designated as “Hickory,” on
which the observers’ stations are
spotted. The equipment consists of a
box containing a 3-position key, two
lamps, and a subscriber’s set circuit.
The user, generally a woman called a
plotter, is warned by a lamp and
buzzer, when a call is on her line. In
addition, a supervisor has a line of
101B Key Equipments in front of her
by which she can intercept calls which
require special attention, or help out
in a peak load. All of the incoming
lines pass through a training and
patching board, for flexibility and so
that Signal Corps men can give the
plotters dummy calls for practice.

Intercommunication between the
various boards and between officers is
afforded by standard circuits, con-
nected to the user’s head or handset
as required. A few long private lines
connect the operations board with
similar boards in other cities, so as to

follow a flight from one area to an-
other. Other lines are connected to
distant Air Corps radio equipment, in
order to give direct communication
with planes in flight.

The Civilian Air Raid Warning
Officer must be able to reach quickly
all of his district warning centers,
but calls to any one center will
necessarily be infrequent. The warn-
ings are therefore sent over toll lines,
There are four kinds of warning—
yellow, blue and red, for varyin
imminence of danger, and white for
“all clear.” Should the movement of
enemy aircraft indicate immediate
danger for the Albany district, the
C.A.R.W. Officer at New York says
to the attendant at his special PBX,
“Albany red.” That attendant plugs
into a red-ringed jack in the “Albany”
group and says to the New York toll
operator who answers, “Albany
red.” At the Albany toll board, the
call is completed over a line which
sounds special signals in the district
office. Receipt of the warning is then
acknowledged by voice, and further
particulars given if desired. On com-
pletion, the P.B.X. attendant leaves
a dummy plug in the red jack as a
reminder of the warning transmitted.

During the air defense maneuvers
the system set up along the north-
eastern seaboard was in practical
operation. A broadcast from the New
York Information Center was ar-
ranged by the Columbia Broadcasting
System during which Captain Wyllis
Cooper, Military Commentator for
CBS, said:

“This is essentially the same warn-
ing and interception system that the
British have used in interdicting large
sections of their island to enemy
bombers. The systems were developed
independently, and we are adapting
British methods to our own use, while

we pass on to them whatever we have
discovered that they don’t already
know.

“The difference between our sys-
tem and the British is this: England
has high-quality telephone service,
but there are relatively fewer tele-
phones. That means that there are
blank spaces that aren’t covered by
observers.

“That’s not the case with us—we
can have more observers because we
have the finest telephone service and
equipment in the world, all concen-
trated under one company; a com-
pany that has been so enthusiastically

helpful in codperating with the Army .
that it can be said with assurance
that it couldn’t have been done with-
out the telephone company. They
have developed special equipment;
their engineers have worked with the
Army over long periods; they have de-
signed and built information centers
and lent their experts to teach people
how to run them; they have done,
are doing, a magnificent job. How-
ever, the essential point about this
whole ingenious system is so sound—
proved so sound in battle—that it
may well be the determining factor
that wins wars.”

Dr. Buckley has received a letter from Colonel Ira C. Baker of the Air
Corps expressing appreciation for the coéperation and assistance
rendered by the Laboratories during the recent Carolina maneuvers.
He says, “Specifically, I wish to thank you for the technical assistance
and advice given us by Mr. L. A. Dorff and Mr. L. A. Yost whom it
was our privilege to have with us during part of these maneuvers.
Mr. Dorff and Mr. Yost not only worked tirelessly but also displayed
unusual ingenuity by installing for the first time in our Army, a
mobile Information Center on wheels.”

The picture shows Mr. Dorff, H. M. Hagland, A. C. Gilmore and
C. W. Halligan discussing the mobile Information Center while it
was being built at the Western Electric Shop at Hudson Street

ACH year more than two mil-
lion splices are made in rubber-
insulated wires by Bell System
workmen. Every one of these splices
involves joining the conductors and
putting on insulation to replace that
which has been cut off. Improvements
have been made in both the materials
and methods; a new tool and new
sleeve have been developed for joining
the conductors, and a new kind of
insulating tape made available.
Rubber-insulated wires used in out-
side plant and station wiring cover a
wide range of characteristics to meet
the various conditions under which
they are installed. At one extreme are
bronze drop wires used for extending
the telephone circuit from a cable
terminal to the subscriber’s premises.
These wires are characterized by high
tensile strength. At the other end of the

range are the station wires, in which
compactness and appearance are pri-
mary factors. These wires are as small
as is consistent with transmission re-
quirements, and their annealed copper
conductors have low tensile strength.

For joining the conductors the prin-
ciples involved in the rolled sleeve
splice for open wires* were utilized to
provide a single-tube pressed sleeve.
Both sleeves are similar except that
the latter is proportionately smaller,
and made of annealed brass. Because
the tension in insulated conductors is
lower and the sleeve-closing pressures
required are smaller, it was found
feasible to apply them with a pressing
tool. This has advantages over a roll-
ing tool from the standpoints both of
size and of convenience.

need for a one-handed tool small
enough to be usable in confined loca-
tions, led to the selection of toggle-
action pliers. As the toggle approaches
dead center, the pressure on the
handles actually decreases and they
snap to the closed position. Stops con-
trol the die closure and thus provide
a uniform splice of good quality.

Although the tool, shown in the
headpiece, weighs only
eight ounces and is ap-
proximately six inches
long, it develops 2000
pounds pressure on a
three-sixteenths inch
length of sleeve with
twenty-five pounds ap-
plied to the handle.
The small size of the
presser was achieved
principally by using
mated concave and
convex bearing  sur-
faces rather than pins
to transmit the loads.
This construction also
minimizes wear and
promotes long service.
The small pins, seen
in the illustration, serve merely to
secure the assembly. Since the bear-
ing pressures on these surfaces are
high, a wax lubricant is employed.

The sleeve presser reduces the di-
ameter of the larger sleeves at least
fourteen mils and that of the smaller
sleeves twelve mils. Nine mils de-
crease in the former and eight in the
latter are adequate to produce full
holding power, so the tool can wear
considerably before it loses its effec-
tiveness.

There are two pressing grooves in
the pliers to accommodate sleeves of
different diameters. The larger groove
is for drop and buried wire and the
smaller one for station and bridle

wire. Sleeves for the 20- and 22-gauge
bridle and station wires are an inch
long and about one-sixteenth inch in
diameter after pressing. Those for
the 17- and 18-gauge bronze and the
14-gauge hard-drawn copper drop
wire conductors differ in bore size but
both types are two inches long and
one-tenth inch in diameter when
pressed. The bores of the latter sleeves

are coated with emery and lacquer, as
are open-wire sleeves, to attain the
high holding power required.

Pressed sleeve splices provide full
mechanical strength and being air-
tight, they make permanent electrical
contact. They have a smooth exterior
and a small diameter; moreover, the
pressing operation elongates the
sleeves, a feature which has been used
in splicing multi-conductor wire. If
the conductors are of unequal length,
after the minimum number of presses
required for adequate holding power
are made in each sleeve, discrepancies
can be rectified by additional presses
in the sleeve on the shorter conductor.
A proper equalization of length dis-

tributes tensile loads equally between
the conductors and, with reasonable
care, splices are produced which ap-
proximate the strength of the un-
spliced wire.

An equally important feature of the
improved splices is the use of a newly
developed rubber tape, known as
“DR” insulating tape, which has a
layer of adhesive rubber bonded to a
backing of vulcanized elastic rubber.
For easy identification the plastic
layer is white and the vulcanized one
black. The tape is always applied with
the white surface next to the con-
ductor, so that the splice is enclosed
in a layer of plastic insulating com-
pound which flows into all the surface
irregularities and bonds securely to
the insulation on the conductor to
form a water-tight seal. The vulcan-
ized layer on the outside provides
mechanical protection for the con-
ductor splice and the plastic material
of the inner layer.

Mechanical protection provided by
the vulcanized layer in the tape, and
the small diameter of the sleeves,
make it unnecessary to splice the indi-
vidual conductors at separated points.
This shortens the length of the splice
and ordinarily eliminates the need for

In splicing wires which have 18.,
I7-, and 14-gauge conductors, each
conductor is insulated individually,
A serving of DR tape is applied with
each turn half overlapping the pre-
ceding one and the tape is stretched in
application. This exerts a constraining
effect on the underlying plastic layer.
Splices made in finer insulated wires,
such as the station wires which have
22-gauge conductors, are protected
by folding the tape longitudinally
around the sleeve and some of the ad-
joining insulated conductor at each
end. Since the tape is 34 inch wide it
will enclose two of these conductors.
With triple conductors the three
splices are pressed between two layers
of tape. Splices in these fine wires
have not previously been protected
with rubber tape but its use has
markedly improved their electrical
qualities. All splices are protected by
an outer layer of friction tape.

Although this development was
initiated primarily to improve the
quality of splices, it became apparent
as the work progressed that the new
splice is actually more economical
than those previously used.

helpful to engineers by making
visible the recurrent variations in
voltage or current at any desired
point of a circuit. Such tubes have four
deflecting plates, arranged in pairs at
right angles to each other. Voltage
proportional to the current or voltage
to be measured is impressed across the
vertical plates, and causes the beam
of electrons to be deflected up or down
in proportion to the intensity at the
point of measurement. Across the
horizontal plates is connected a volt-
age that varies as shown in Figure 1.
From A to B there is a steady rise in
voltage that moves the electron
stream steadily from left to right for
the workable width of the tube. From
B to c, which is made not more than
one-tenth of the time from A to B, the

voltage drops rapidly to its original
value, and the electron stream re-
turns rapidly to the left side of the
tube. This latter voltage cycle is pro-
vided by a “‘linear sweep circuit’ *—
a name that is descriptive of the
function performed.

Previous oscilloscopes have usually
employed a gas-filled tube in the
sweep circuit. The AB section of the
sweep cycle results from the charging
of a condenser in the plate circuit. At
point B the tube breaks down; the gas
becomes ionized, and the condenser
discharges through the ionized gas.
Before the condenser can start its
charging cycle, however, the gas in
the tube must become deionized so
that the tube will be non-conducting,
and this deionization requires a small
but appreciable time. Because of this

deionization time, a sweep circuit of
this type is not suitable when the
frequency to be measured is greater
than about 100 ke. Until a few years
ago such a frequency was high enough
to cover most of the studies being
made, but with the increasing use of
higher frequencies in recent years, a
need has been felt for a high-frequency

sweep circuit. Such a circuit was de-
veloped by using a high-vacuum tube
to provide the sweep frequency. No
deionization is involved with such a
tube, and it has been possible to
secure sweep frequencies up to one
million cycles. This permits frequen-
cies as high as ten megacycles to be
satisfactorily displayed. Along with
the development of this new sweep
circuit, it was necessary also to pro-
vide high-gain high-frequency ampli-
fiers for use between the sweep circuit
and the circuit under test and the
plates of the cathode-ray tube.

The circuit employed to provide the
sweep frequency is shown in simplified
schematic form in Figure 2. The sweep
voltage, £3, is taken off across the
condenser c3 in the cathode circuit of
tube v2. When this condenser is
charged to a voltage higher than £1,
the cathode is at a higher potential
than the grid, and current flow
through the tube ceases. The con-
denser then stops charging and at
once starts to discharge through the
high-resistance R3. The discharge cur-
rent of a condenser through a re-
sistance decreases exponentially with

time, but over a short initial section
of the discharge, the decrease jis
nearly linear, and it is this essentially
linear drop that provides the section
AB of the sweep cycle.

During this discharge period, tube
VI is passing current, and its plate
current passing through R4 reduces
the voltage of the grid of tube v2
below EI. As the condenser continues
to discharge, £3 finally falls below the
voltage of the grid, and at some
definite voltage—fixed by the charac-
teristics of the tube and the operating
voltages—v2 starts to pass current.
As soon as plate current flows, the
voltage ES drops because of the volt-
age drop of the plate current through
RS. This reduction in £5 results in a
decrease in the grid voltage of v1
through the coupling condenser c1.
The reduced grid voltage of vi re-
duces the plate current of v1, and the
decreased current flow through rq in-
creases the grid voltage on v2. As a

result there is a rapid increase in the
plate current of v2, and the condenser
c3 charges very rapidly.

As it charges, the voltage £3 rises,
thus decreasing the flow of plate cur-
rent in v2, and resulting in an increase
in ES because of the decreasing drop

across R5. This rise in E5 again aftects
the grid potential of v1, increasing the
plate current of v1 and thus decreas-
ing E4, which is impressed on the grid
of v2. This decrease in £4 together
with the increase of £3 very quickly
blocks the flow of current through v2,
and another cycle is ready to begin.
This interaction between the plate
voltage of v2 and the grid voltage of
vi, and between the plate voltage
of v1 and the grid voltage of v2, results
in a very rapid increase and decrease
in the plate current of v2. The com-
plete increase and decrease takes
place during the period sc of the
sweep cycle, and it is during this very
short interval that the electron stream
of the cathode-ray tube is returned
from the right end to the left.
Condenser c3 is adjustable in steps,
and R3 is continuously adjustable.
Since it is the relative value of these
two elements that determines the
sweep period, the sweep frequency is
continuously adjustable. The range is
from twenty cycles to one megacycle.
For proper functioning of the oscillo-
scope, the sweep frequency must be
some exact submultiple of the funda-
mental frequency being observed;
that is, it must be such that there are
exactly I, 2, 3, 4, or more complete
cycles of the observed wave on the
front of the tube. To secure this syn-
chronization, c3 and R3 are set to the
approximately correct values, and the
precise sweep period is obtained by
feeding a portion of the observed
voltage to the vacuum tube v2. The
value of this voltage has considerable
influence on the point at which dis-
charge of v2 begins, and by supplying
it with an adjustable portion of the
voltage on the vertical plates of the
cathode-ray tube, the sweep cycle can
be made to begin always at the same
point of the wave being studied.

To deflect the electron stream to °
full width of the cathode-ray tube, po-
tentials of several hundred volts are
required. It is necessary, therefore, to

SYNCHRONIZING
CONNECTION
OUTPUT
STAGE
LI
lo
STAGE
LL LI
PHASE
INVERTER
w
LL | .
2ND =
STAGE | <
N
z
<
an
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a
z
INPUT | >
STAGE
TEST
SWEEP
CIRCUIT PROBE

use amplifiers between the sweep cir-
cuit and the horizontal plates and
between the voltage to be studied
and the vertical plates. The output
required is the same for both ampli-
fiers and the frequency range required
is of the same order of magnitude. It
seemed desirable, therefore, to use
identical amplifiers in the interest of
flexibility. It was desired that the
amplification be substantially con-
stant from three cycles to ten mega-
cycles, but the greatest difficulty in
the design was to secure sufficient
load capacity without wave distortion
at the peak voltage.

At their output, these amplifiers
must be connected push-pull because
the deflecting plates of the cathode-

ray tube must be balanced with re-
spect to the anode of the tube. The
input, however, should be unbalanced
because the most common measure-
ments are of voltages to ground.
Moreover, it is desirable to view the
wave form without disturbing the cir-
cuit being studied, and for this reason

Fig. 4—A two-megacycle wave as shown by
the new oscilloscope; above, nearly semi-
soidal; below, a distorted wave

the input of the amplifier should be of
very high impedance. At ten mega-
cycles, high impedance is difficult to
secure since the capacitance to ground
of even short lengths of wire may
result in impedances lower than the
desired value. For these reasons, the
first stage of the amplifier was
mounted in a small aluminum shield

and connected to the second stage by
a shielded cord to permit the amplifier
itself to be taken to the point of the
test circuit where the voltage is to be
taken off. This first-stage amplifier
has two short prongs to which the
connection to the test circuit is made.

A block schematic of the entire
oscilloscope is shown in Figure 3. The
first-stage amplifiers on their flexible
cords are called “probes,” and one is
connected to the circuit under test
and the other to the sweep circuit.
The third-stage amplifier acts as a
phase inverter to transform from an
unbalanced to a balanced circuit. The
connection from final stage of the test
amplifier to the sweep circuit runs to
the screen grid to control the timing
as already noted. |

The two amplifiers, the sweep cir-
cuit, and the cathode-ray tube are all
mounted on a single frame as may be
seen in the photograph at the head of
this article. Rectifiers are provided on
one of the lower panels so that the
instrument may be cperated from a
11s-volt a-c line. About 4co watts is
required. Regulators are included to
prevent variations in the a-c power
line from affecting the operation of’
the oscilloscope. Oscilloscopes like
this one have already proven very
useful in the carrier systems labora-
tory, especially for checking singing
conditions in feedback amplifiers.
Since the horizontal time scale can be
extended until ten inches represents
one-millionth of a second, it is pos-
sible to observe recurrent phenomena
whose time of duration is very short.

Looking from the Acoustics Laboratory toward the main group of buildings at Murray Hill.
The Restaurant and Club Rooms are in the low structure shown in the left foreground

HEN I last spoke to you, just about a
year ago, I told you that the Bell
System was ready to do its part on all fronts
in the nation’s defense program. Now, after
twelve months, and on this Armistice Day
eve, I want to tell you how the job has been
going. First of
all, it is a big
job—the biggest
we have ever
been called upon
to perform and
it has been tack-
led with the de-
termination to
do the impossible
rather than try-
ing to show why
the possible can’t
be done.

Everywhere people have been reaching
for the telephone to speed the defense job.
This has meant a tremendous increase in its
use and we now have to handle many mil-
lions more telephone calls a day than we did
a year ago. Army
campsand Naval
bases, shipyards,
airplane facto-
ries and muni-
tion plants have
had to have new
or greatly ex-
panded tele-
phone facilities
—most of them
with the word
“RUSH” writ-
ten all over
them, and many of them in areas that a
year ago were cornfields or sand dunes.

Yes, it is a big job, because we must
maintain all telephone service at a high

level if calls vital to national defense are to
be sure to go through quickly. Let me jl.
lustrate. Just the other day we received a
letter from a man in Buffalo. In it he
thanked us because a long distance call he
made to San Francisco had been completed
in a moment or
so. He said that
in this case we
had done an un-
usual service be-
cause the call was
of very great im-
portance to the
defense program.
Well, naturally,
telephone people
like to get such
thanks. But the
fact of the mat-
ter is that no special consideration was given
to that particular call, for we don’t know
which call, of those pouring in upon us, is the
important one to national defense. To be
sure of serving defense needs, a// calls should
go through
swiftly and ef-
ficiently.

I hope you will
agree that we
have so far suc-
cessfully met the
demand for tele-
phone service,
great as it has
been. Because of
conditions be-
yond our con-
trol, such as the
shortage of copper and other essential ma-
terials, it may be, as time goes on, that we
cannot continue to mect the demands with
the same success. However, I pledge you

The telephone and the radio are essential
in very special ways in military operations.
Fast-moving tanks and airplanes, for in-
stance, keep in touch with their commands
by radio telephone. The Air Raid Warning
Service relies on what are called “radio-
sentries” and on civilian observers who tele-
phone their observations of enemy aircraft
to the proper de-
fense center.
These and many
other military
needs mean new
communication
devices. We have
about a hundred
different mili-
tary research
jobs under way
and a large pro-
portion of the
2,000 scientists
and engineers in our Bell Telephone Labora-
tories are devoting their full time to this work.

Our manufacturing branch, the Western
Electric Company, is supplying great quan-
tities of telephone and radio equipment for
the Army and the Navy. Among the many
things that are being produced are tens of
thousands of radio telephone sets for training
and combat planes. Also, there are special
field telephones, switchboards and wire for
the Army, and complete communicating
systems for new battleships and for aircraft
carriers. There are many other new devices,
such as, for instance, a new microphone for
the pilots of fighting planes which fits
around the pilot’s throat, so that the sound
of his voice can be heard clearly, without
interference from noise. All of this inventing,
designing and making of military equipment
is an important part of our defense responsi-
bility and is in addition to our regular but
greatly increased telephone task.

In conclusion, I want to express my sin-
cere appreciation to the 380,000 men and
women of the Bell System for a big job
being done in the best Bell System tradition.
The credit for this big job goes first to them.
Then it goes back further to the system of
private initiative and free enterprise which
made it possible for them to develop their
skills and their abilities. And then, finally,

Wave anp NEtTWorKS
IN THEORY AND PRACTICE
THREE MEMBERS of the Laboratories—

H. A. Arrez, A. J. Grossman and A. R.
D’HEEDENE, were chosen by the Communi-
cation Group of
the
New York sec-
tion to partici-
pate in a lecture
series On wave
filters and other
networks which
was concluded
on December 1.
The seven lec-
tures of this
course empha-
sized the practi-
cal design, use and theory of communication
networks.

Mr. Affel presented the introductory lec-
ture, Functions of Filters and Other Networks,
on October 20; Mr. Grossman discussed
Filter Design Practices and Attenuation and
Phase Equalizers on November 10 and 24,
respectively; and Mr. D’heedene, Crystal
Elements in Wave Filters on November 17.
The other lectures were General Network
Theory and General Wave-Filter Theory by
Prof. E. A. Guillemin, M.1.T., and Coaxial-
Line Elements Applied to Filters and Net-
works by C. W. Hansell and P. S. Carter,
R.C.A. Communications.

After many months of hard work and prepa-
ration by the Army, Telephone Companies and
Civil Defense units, the Air Defense System has
been completed in a portion of the vital North-
eastern Area, and our recent test proved to the
satisfaction of the Army that with minor changes
the system is adequate.

installations at Information and Filter Centers
in time for maneuvers, long hours of hard work
were necessary. This was accomplished with
much credit to you and your organization.

I wish to express my deep appreciation to
you and, through you, to your organization,
especially Mr. A. Tradup and his associates,
and Mr. C. W. Halligan and his associates, for
the splendid work and coéperation which made
all of this possible.

Our NEw sBuiLpING at Murray Hill
crossed the line from project to actuality on
Monday, November 17, when 140 members
of the Laboratories reported there for work.
Parking their cars or alighting from busses,
they entered the building, to find their
desks in place with telephones connected and
building services ready for their needs.

Since the Outside Plant Development
forces had been selected as the first group to
be moved, work was begun several days
earlier on the heavy laboratory equipment
at West Street. Every piece was tagged for
the space it was to occupy at Murray Hill,
including desks, files and chairs. Under the
general direction of J. G. Morey, construc-
tion engineer for the project, the move was
handled by A. F. Leypen of the Plant
Department with the assistance of R. L.
Towne of Apparatus Staff.

Engineers must look to others for many
services, so members of several other de-
partments accompanied them to Murray
Hill. They came for the most part from
‘Drafting, Apparatus Staff, General Service,
and Plant, but Publication is currently rep-
resented by Miss Levesque, the recep-
tionist; Personnel by F. D. LEamer and
his staff; and Financial by Frank Boy e.
At noon on Monday the restaurant formally
opened for cafeteria service with a line
headed by R. A. Hatstip, Director of Out-
side Plant Development. A bus company
furnishes service between the building and
the railroad station in Summit. Automobile
service primarily for departmental mail is
available to New York with three round trips
daily; passengers will be carried on company

M. B. Long who has been responsible for the
coordination of construction and related opera-
tions at Murray Hill

business up to the capacity of the car.
Telephone service is given at Murray Hill
by a dial PBX with thirteen trunks to the
Summit central office and ten tie lines to the
West Street board.

About the middle of December the Metal-
lurgical group and their laboratory will go to
Murray Hill. Later Station Apparatus De-
velopment, the Physical Research, and Cir-
cuit Research people and the rest of the
Chemical Laboratories will move; then the

E. I. Green, at the October 20 meeting of
the Colloquium, spoke on Automatic Curve
Tracing in Telephone Transmission Measure-
ments. The ever-increasing number and vari-
ety of measurements required in telephone
transmission work has necessitated recourse
to automatic measuring techniques. New in-
struments have been developed for tracing
automatically, on a recording chart, con-
tinuous curves of amplitude, phase, etc.,
versus frequency. Devices are also available

whereby such characteristics can be thrown
instantaneously on a fluorescent screen for
observation and analysis. Examples were
iven of mechanized measurements of both
the recording and viewing types, including
schemes already being used and others ex-
pected to be needed in the future.

Dr. W. E. Forsyte of the Lamp De-
velopment Laboratory of the General Elec-
tric Company discussed The Scientific Aspects
of Recent Radiation Sources at the November
3 meeting. Dr. Forsythe, who has been
prominent in the development of new radia-
tion sources, described the radiating charac-
teristics of some of the newer tungsten lamps,
including the “‘sealed-beam” headlight lamps
and some of the projection lamps made after
this pattern. The constructional details and
radiating characteristics of the new intense-
mercury arcs were also discussed. He then
considered the new fluorescent lamps and

showed the radiating characteristics of the
low-pressure mercury arc used to excite the
fluorescence in these lamps and the radiating
characteristics of various fluorescent pow-
ders when they are excited with this low-
pressure arc.

THE HANDLING OF CuristMas holiday toll
traffic presents one of the most difficult
service problems. Not only are there more
calls in most offices on Christmas Eve and
Christmas Day than in other comparable
periods, but the calls are longer haul, go to
many more small places, involve more
switching, and require more operating time
per call than on normal days.

In view of the present trend in toll board
business the traffic experts in the telephone
organization expect that the Christmas holli-

Setting one of the machines used in the mechanical laboratory of the Outside Plant Development
Department at Murray Hill

day load this year will be heavier than ever
and service more seriously affected. The
telephone-using public will be informed of
the critical service situation and its co-
operation requested. Employee codperation
is expected not only in advising the public
of service problems which the Christmas
traffic will present but in refraining from
making personal calls during the holiday
period.

THIRTY-FOUR EDITORIALS commenting
favorably about telephone matters in rela-
tion to the defense effort appeared during
July, August and September in newspapers
scattered over the country. Developments
of the Laboratories underlay twenty-two of
these editorials—saving and substituting of
materials in nineteen and the safety of
underground toll cable in three.

THERE WAS A GAIN of about 120,300 tele-
phones in service in the Bell System during
October, making the net gain for the first

ten months of this year 1,128,300 as against
748,300 for the same period in 1940. At the
end of October there were about 18,609,400
telephones in the Bell System.
* * * * *
THE Paciric TELEPHONE AND TELEGRAPH

Company reports that in one month they
installed about 22,000 new telephones as

Staff Sergeant Bukur of the 2nd Battalion,
71st Infantry, using a field telephone set during
maneuvers in the Carolinas

compared with 16,000 for the same month
last year. A lot more long distance calls are
being made in that section. The company
has added nearly seven thousand people to
its payroll, and is spending this year more
than $75,000,000, mostly for construction to
take care of the unusual service demands.

Mitirary ITEms
MemMBERS OF THE LaBoraToRIES who
have been granted leaves of absence for
military service since the last issue are:
Cuartes T. Boicer, Troop A, First
Training Squadron, Building 2041, C.R.T.C,
Fort Riley, Kan.

Raymonp P. Cuapman, Company A,
35th Infantry Training Battalion, Camp
Croft, S. C.

GeorceE R. Srisirz has been granted a
leave of absence in order to engage in Na-
tional Defense Research Committee work
for the Office of Scientific Research and De-
velopment.

THE FOLLOWING MEMBERS of the Labora-
tories have returned from military service:
Tuomas J. Gitcurist, Haroitp W. Kowa,
Kart J. Ocaarp, Paut F. Pererson and
Joun H.

Lizur. Einar RetnBerG, who took the
photographs shown on these two pages,
writes from the present army maneuvers in
the Carolinas:

The 71st Infantry since its induction Septem-
ber 16, 1940, has traveled twice to Fredericks-
burg, Va., and Ft. Meade, Md.; once to Indian-

I have served in this Regiment as an enlisted
man and officer for thirteen years. Since induc-
tion (Sept. 16, 1940) as a 2nd Lieutenant I have
been appointed a 1st Lieutenant and recently
assigned as Adjutant of the 3rd Battalion.

Communications, which used to play a big
part in Battalion Headquarters Companies
under the old table of organization, have been
“streamlined,” leaving the message center and
semaphore signaling as their only responsibility.
The “Company” is now known as a “Detach-
ment.” Field telephones and “walkie-talkies”
(radios) are supplied with operators from Regi-
mental Headquarters Company.

We have started our additional eighteen
months’ service by roughing it in the field, bed-
ding down wherever we stop and living in pup
tents. The boys have overcome the fear of snakes

THE ANNUAL AWARD of the Associated
Grocery Manufacturers of America was pre-
sented to R. R. WitiiaMs at a meeting held
in New York on November 6. The award

First Sergeant Nils Anderson of the 2nd Bat-
talion, 71st Infantry, with “walkie-talkie” in
carrying position

Left to right around table—O. E.
Buckley, Mrs. Buckley, W. Wilson
Mrs. Wilson, A. B. Clark, Mrs. G.B
Thomas, Leo Montamat, Mrs. Monta.
mat, Mr. Thomas and Mrs. Clark

read: “This Award of Distinction is pre-
sented to Robert R. Williams, M.S., D.Sc.,
in recognition of his outstanding and funda-
mental contributions to our knowledge of
vitamin By, carried on over a period of many
years and culminating in the isolation, syn-
thesis and naming of this essential dietary
factor—results of far-reaching significance to
the science of nutrition and to food tech-
nology.” The presentation was made by
Paul V. McNutt, Federal Security Adminis-
trator, and Dr. Williams, in his acceptance,
spoke on Where Do Vitamins Come In?

R. K. Porrer has been appointed Re-
search Engineer reporting to the Director of
Research. Mr. Potter will act as technical
aid in connection with research and develop-

ment programs for defense that are being
carried out for the Western Electric Com-
pany by the Laboratories.

H. S. SHepparp, before the recent con-
vention of the North Carolina Independent
Telephone Association, spoke on recent de-
velopments made by the Laboratories.

DurinG THE WEEK of October 20 several
members of the Laboratories either partici-

pated in or attended meetings of several
societies which held meetings in the Penn-
sylvania Hotel, in New York City. The
societies were the Acoustical Society of
America, the Optical Society of America,

the Society of Rheology, and the Society of
Motion Picture Engineers. Papers presented
were Pressure Radiation in Moving Systems
by H. E. Ives before the Optical Society;
and Apparatus for the Direct Measurement of
Force-Displacement Characteristics of Me-
chanical Systems by J. R. Haynes before the
Acoustical Society.

THE TRUSTEES OF PRINCETON UNIVERSITY
have elected O. B. Biackwe ut and P. B.
FINDLEY to membership on the Advisory
Council of the Department of Electrical
Engineering and W. A. SHEWHaRT to mem-
bership on the Advisory Council of the De-
partment of Mathematics. Mr. Blackwell
has been a member for several years of an
informal group of outstanding electrical
engineers who performed the same functions,
and Mr. Findley, an alumnus, is a member
of the executive committee of the Princeton
Engineering Association.

THE Ocroser IssuE of The Journal of the
Acoustical Society of America carries three

At the rate of twenty a week, upwards of 300 radio transmitters, designed for ground-to-plane

communication, are rolling off the assembly lines at Western Electric’s Kearny Works for

delivery to Pan American Airways System. These transmitters will form a vital part in Pan

American’s far-flung communications system which links the flying Clippers to terminals in

the United States, Alaska, South and Central America, Africa, New Zealand, the islands of the

Pacific, and the Far East. The transmitters are of the 300-400-watt class, and were designed by
the Laboratories to Pan American specifications

articles by members of the Laboratories
which discuss the stereophonic sound film
system. They are General Theory by Harvey
FLETCHER; Mechanical and Optical Equip-
ment for the Stereophonic Sound Filin System
by E. C. R. L. A.
Fimer and A. B. ANDERSON; and, Stereo-

phonic Sound Film System—Pre- and Post-
Equalization of Compandor Systems by J. C.
STEINBERG.

R. M. Bozorru attended the National
Metal Congress and Exposition at Philadel-
phia. He was chairman in charge of the joint
technical session of the Institute of Metals

MEMBERS OF THE LABORATORIES TO WHoM Patents WERE IssuED
Durinc THE MontH oF OcTOBER

R. H. Badgley J. F. C. Dahl
M. W. Baldwin, Jr. R. C. Davis
W. R. Bennett P. B. Drake
H. H. Benning L. L. Eagon
B. G. Bjornson I. E. Fair

H. S. Black (2) P. B. Flanders
J. R. Boettler F. Gray (3)
A. E. Bowen R. O. Grisdale
D. E. Branson R. B. Hearn
A. J. Christopher G. Hecht

A. C. WALKER discussed Drying of Tex-
tiles before a group meeting of textile school
deans held in New York on November 13.
Following the meeting the group came to the
Laboratories for an inspection trip which
covered laboratories of particular interest in
their work.

J. C. STEINBERG took part in discussions
of hearing-loss disability ratings at the
annual meeting of The American Academy
of Ophthalmology and Otolaryngology held
in Chicago’on October 23.

E. E. ScHuMACHER was in Philadelphia
on October 21 where he participated in the
0.P.M.-A.S.M. National Defense Meeting
dealing with Conservation of Copper. He

Metallurgy held on September 25 and 26 at
the Massachusetts Institute of Technology
and presided as chairman of one of the four
technical sessions.

C. S. Futter and B. S. BicGs visited the
Research Laboratory of the Resinous Prod-
ucts and Chemical Company, Bridesburg,
Pennsylvania, in con-
nection with plastics
problems.

R. M. Burns at-
tended the Electro-
Chemical Society Con-
vention which was
held in Chicago.

C. C. Hipxins, in
Washington, attended
the monthly meeting
of the Protective Coat-
ings Section of O.P.M.

G. L. Pearson pre-
sented a paper en-
titled = Thermistors —
Their Characteristics
and Uses before a
meeting of the Metro-
politan section of the
American Physical
Society, held in New
York City.

C. Maccs of the
Electronics Research
Department received
a B.S. in M.E. degree
from New York Uni-
versity in October.

A paper on Some A-C Properties of Paper
Dielectrics Containing Chlorinated Impreg-
nants was presented by D. A. McLean and
C. C. Hourz at the annual meeting of the
National Research Council held at Williams-
burg, Virginia. S. O. Morcan presided at
one session of the Conference that was de-
voted to substitute insulating materials.
W. A. Yacer and L. Ecerron also attended
this meeting.

K. K. Darrow spoke on Physical and
Chemical Forces at the first meeting of the
1941-1942 season of the Radio Colloquium,
held at the Deal Laboratory on November 7.

At THE HawTHorne PLANT of the West-
ern Electric Company, J. R. Barps.ey dis-
cussed the design of a submarine loading-coil
case for The Pacific Telephone and Telegraph
Company and miscellaneous problems on
loading-coil cases in general; T.S. HuxHam,
plastic housing for the combined telephone
set; H. A. FrepericK and C. G. McCormick,
step-by-step equipment problems; G. E.
Atkins, manufacturing problems on the
204-type selector; E. J. Kane and F. A.

At the Fall Social Meeting of
the Edward J. Hall Chapter
of the Telephone Pioneers of

Left to right around table—D. T.
May, H. A. Frederick, Mrs. H. O.
Siegmund, Mr. Siegmund, Mrs. J. R.
Townsend, Mr. Townsend, Mrs.
J. J. Kuhn, Mr. Kuhn and Mrs.
May. Mrs. Frederick, who sat be-
tween Mr. May and her husband, is
just out of the photograph

Right foreground and around table
counter-clockwise—W. A. Bollinger,
W. A. Olson (Long Lines), C. G.
Von Zastraw, P. A. Jeanne, W. E.
Mougey, A. F. Price, E. Vroom,
F. R. Lack (Western Electric), A. H.
Inglis and A. H. Leigh. This entire
group were in the Research and In-
spection Division of the Signal Corps
during the First World War and
served together in France

WILLIAM FonpDILLER and C. A. WEBBER
visited the Point Breeze plant of the Western
Electric Company in connection with cord
development problems.

J. R. TownsenD and W. E. INGERSON at-
tended a meeting devoted to Indentation
Hardness and sponsored by the American
Society for Testing Materials, the American
Society for Metals, and the Society of Auto-
motive Engineers. The meeting was held in
Philadelphia.

H. E. DeCamp, I. G. BarBer and H. P.
Heatu of the Hawthorne Works of the
Western Electric Company visited the Lab-
oratories to discuss common problems in
connection with developments that are now
in progress.

C. Ertanp NE son was in Pittsburgh in
connection with panel-bank contact studies.

F. F. Romanow, on November 14,
gave a talk on the calibration of sound sys-
tems before the Graduate Seminar at the
Brooklyn Polytechnic Institute.

W. M. Bacon, T. L. Corwin and W. R.
Younc were in Cleveland to test the 81B1
private-wire teletypewriter system installed
for the Republic Steel Company. Commer-
cial service started October 1 and on October
jo E. F. Watson observed its operation.

Henry H. Hatt
of the Commercial Relations
Department completed thirty-
five years of service in the
Bell System on November 15

Epmunp F. KercHaM
of the Equipment Develop-
ment Department completed
thirty-five years of service in
the Bell System on Nov. 24

August Koernig assembling an amplifier
chassis in the Development Shop

G. E. Srowe and R. B. Simon visited
Princeton and Philadelphia in connection
with the coaxial-cable trial installation be-
tween New York and Philadelphia.

F. R. Dickinson and T. J.
O’NEIL are supervising the
installation of the new car-
rier telephone equipment for
the Key West-Havana sub-
marine cable.

J. E. Greene, in Chicago,
discussed additions to the
Oakland crossbar office with
engineers of the Illinois Bell
Telephone Company.

MACHINE DESIGN PROB-
LEMS took J. H. Soe to the
Pioneer Gen-F-Motor Cor-
poration in Chicago and to
the General Electric Com-
pany in Fort Wayne, Ind.

J. L. Larew was at Read-
ing, Harrisburg and Lewis-
town, Penna., on matters
pertaining to the power
equipment for the K2 carrier
trial between New York and

Pittsburgh. J. L. Axttson, in connection
with the same trial, visited repeater stations
at Ligonier and Pittsburgh.

R. P. Jurson went to Eau Claire, Wis.,
where he discussed power problems associ-
ated with the coaxial installation between
Stevens Point and Minneapolis.

DuRING THE MONTH OF NovEMBER the
foliowing members of the Laboratories com-
pleted twenty years of Bell System service:

Systems Development Department
A. F. Grenell C. R. Meissner
Miss Fay Hoffman T. D. Robb

AFTER RECEIVING his B.S. in E.F.. degree
from Rutgers University in 1915, Harry B.
SMITH spent a year with the Public Service
Company of New Jersey and six months in
reinforced concrete and steel construction
work. His first work in the Engineering De-
partment of the Western Electric Company,
which he joined in 1916, was on the life
testing of step-by-step switching apparatus.
During most of the war period he was con-
cerned with special machine-switching appa-
ratus for government use. Later he spent

several years on the development of measur-
ing apparatus in the electrical design group
of the Special Products Department.

From 1927 to 1938 Mr. Smith was in the
apparatus analysis laboratory where he was
concerned with investigations of contact
noise and resistance of base metal contacts.
During the early development of the cross-
bar switching system he was engaged in
testing this apparatus. In 1938, when cost
reduction studies on the crossbar switch were
being made, he transferred to the dial appa-

Development Department and since then
has been associated with the design and
analysis of the card-operated crossbar
switch and of the multi-contact relay.

Mr. and Mrs. Smith live in Plainfield,
N. J., and have one daughter who is married.
His hobbies are gardening and woodwork-
ing. Mr. Smith is a charter member of the
Plainfield Mendelssohn Glee Club and a
member of the Edward J. Hall chapter of
the Telephone Pioneers of America.

SINCE 1929 JouN J. Couttns has been in
the Metallurgical Laboratory where he has
been engaged in the fabrication of wires and
tapes from precious metals and alloys. His
principal work has been the rolling of fila-
ment tapes for vacuum tubes and the rolling
of magnetic recording tape. The production
of this recording tape has required consider-
able“ingenuity and patience on his part.

Mr. Collins was with the manufacturing
organization of the Western Electric Com-
pany at West Street for three short periods
from 1909 to Ig911. In 1918 he joined the
yacuum-tube shop where his work was on
vacuum tubes for government uses. Follow-
ing the war he was placed in charge of the
maintenance of pumping stations in the tube
shop. From 1921 until he transferred to the
Metallurgical Laboratory he was a main-
tenance electrician in the Plant Department.

The Collinses, who live in West Norwood,
N. J., have four sons. Three of these boys
are in service—Wilfred, a corporal with the
165th Field Artillery; Edward, with 1o4th
Engineers; and Thomas, a seaman on the
U.S.S. Prairie. Their youngest son is in
elementary school. Mr. Collins is an ardent
deer hunter.

AFTER COMPLETING a two-year course at
Pratt Institute in machine design, Paut C.
SEEGER joined the Engineering Department
of the Western Electric Company. His first

work was in the Apparatus Drafting De-
partment where, for twelve years, he was
concerned with the drafting phases involved
in the development of panel and step-by-step
systems and associated apparatus, such as
dials, relays and keys. In 1928 Mr. Seeger
transferred to the Apparatus Specifications
Department where he has since been en-
gaged with the preparation of specifications
covering coils, transformers and various
types of testing apparatus.

Mr. and Mrs. Seeger, who live in East
Rutherford, N. J., have two daughters in
elementary school. Mr. Seeger is an ardent
gardener and during vacations at Montauk,
Long Island, does a great deal of fishing.

THE ANNUAL MEETING of Technical Draw-
ing Association was attended by A. B. S.
Kvaat and W. A. Biscuorr. This meeting
was held in Chicago on October g and Io.

J. M. Ducuin discussed ringing-machine
development with engineers of the Northern
Electric Company in Montreal.

In response to the request for books to be added to the Camp Monmouth library, members of the

Laboratories brought in approximately 1500 volumes. Morton Sultzer (center) and D. D.

Haggerty are looking over a part of the collection while Miss C.W. Ackerman pastes in special
bookplates indicating that the books were donated by Laboratories people

L. J. Sracy and P. Winsor visited Hart-
ford where they continued their field study
to determine the operational characteristics
of step-by-step switches.

T. D. Ross went to Wilmington, Del., in
connection with a trial installation of sup-
plementary position cabinets for “outward”
operators.

R. K. Honaman has been elected a mem-
ber of the Municipal Council of Glen Ridge.
He was nominated by the Civic Conference
Committee—unique in New Jersey munici-

palities—which considers a large number of
suggested names without political bias.
M. B. Lonc is also a member of the Council.

PrerRE Merzz is the author of an article
entitled Television—The Scanning Process
published in the October issue of the Pro-
ceedings of the I.R.E.

SEVERAL MEMBERS OF THE LABORATORIES
were installed recently as officers of Western
Electric Post 497 of the American Legion at
that organization’s regular October meeting
held in the Hotel Taft. The Post originally

AT THE ANNUAL INSTALLATION MEETING OF WESTERN ELECTRIC
Post 497 OF THE AMERICAN LEGION

Top left—County Commander Lawrence J. McNally installing L. E. Gaige as the new Com-
mander. Top right—F. T. Deputy, British Purchasing Commission, formerly with ERPI,
E. G. Andrews and A. J. Akehurst. Bottom—A. H. Inglis, L. E. Gaige, W. A. Bollinger,
Major James V. Demarest of the United States Army and S. G. Timmerman of the Western

Conference at Murray Hill between those responsible for the design and construction of the
Laboratories and those who will be responsible for its building plant and services. Left to right:
C. A. Chase, T. J. Crowe, E. V. Mace, P. Venneman, M. B. Long and J. G. Motley

consisted of employees of that branch of the
Western Electric Company which was lo-
cated at 463 West Street. It retained its
identity in spite of the fact that its mem-
bership roll was made up almost exclusively
of Bell Laboratories veterans when that
company was formed later.

The new Commander is L. E. Gaice who
succeeded S. G. Timmerman of the Western
Electric Company. Officers installed with
Commander Gaige include H. R. Allen,
First Vice-Commander; O. H. DantEtson,
Second Vice-Commander; L. B. Eames,
Third Vice-Commander; A. H. INGtts,
Adjutant; J. R. Barpstey, Assistant Adju-
tant; S. H. Loverine, Finance Officer; J. F.
Beattie, Service Officer; S. L. Leverone,
Chaplain; and H. Bongard, Sergeant at
Arms. The Executive Committee consists
of L. H. Aten, E. G. Anprews, D. S.
Cloughly, R. B. Ferris, E. C. Hacemann,
F. T. Meyer, F. J. Pracunaix, S. J.
STRANAHAN and M. F. Travers.

P. F. Jones was in Pittsburgh and H. C.
Franke and L. R. Montrort were at va-
rious intermediate points in connection with
the trial of the type-K2 carrier telephone

Joun Mattetr and Miss E. REentrop re-
turned to New York after making static
noise tests at type-K frequencies at various
points along the Omaha-Denver cable route.
Miss Rentrop subsequently returned to
Ogallala, Nebr., to take part in crosstalk
tests at type-K frequencies on this cable.
Others engaged in crosstalk studies in the
vicinity are C. O. Cross, C. H. Gorman,
H. B. Noyes, W. E. Rerp and E. S. Witcox.

D. F. Horu has been investigating meth-
ods of reducing resistance unbalance in
exchange cables at locations in New Jersey
and Long Island.

THE Stevens Pornt-MINNEAPOLIS co-
axial system was turned over to the Lab-
oratories for a period of one month for
special studies. During this period H. H.
Benninc, M. E. Campse.i, B. Dysart,
M. M. Jones, R. R. Brarr and P. G.
Uppstrom carried out transmission measure-
ments for use in the design of systems
longer than 200 miles, and G. R. Frantz,
S. A. Levin and I. E. Woop were in
Eau Claire for equalization studies. K. C.
Biack went to Minneapolis at the time the

L. A. O’Brien, E. H. SHarkey and
K. D. SmirH have returned from Chicago
where they supervised the construction of
apparatus for the Army.

O. D. GrismorE spent some time in Balti-
more arranging for the installation of appa-
ratus for an o.8-mc coaxial trial on the
Baltimore-Washington cable.

LecTurEs on coaxial terminal equipment
were delivered by R. FE. Crane before the
Long Lines Training School held recently at
32 Sixth Avenue.

R. W. Lance returned from Boston where
he had been stationed for over four months
in connection with the trial of carrier-
program facilities over the New York-
Boston Ki systems. J. Maurusnat, Jr.,
carried on the work at Boston until the end
of the trial, then moved to Pittsburgh with
the terminal equipment in preparation for
the coming tests of program transmission
over K2 carrier telephone facilities between
New York and Pittsburgh.

R. S. CaruTHErs went to Salt Lake City
and Wyeth (Oregon) to codperate in clearing
troubles encountered in a new installation
of J2 systems.

Breeze Works of the Western Electric Com-
pany in connection with the construction of
the Philadelphia-Baltimore coaxial cable.

O. R. Garrietp and J. O. Smeruursr
were in Norfolk and Cape Charles, Va., to
test and place in service the twelve-channel
radio telephone system connecting these
points and spanning Chesapeake Bay. A. C
Dickieson and P. G. Epwarps inspected
the arrangements during the testing period.

H. S. Winsicter, A. W. Leserr and V. J.
Hawks spent some time in Miami on field
engineering tests of a new two-channel bank
circuit. The New York terminal of this
experimental circuit was operated by L.
Scuorr and C. W. Carrer, Jr.

In connection with the trial of K2 car-
rier systems, the following engineers were at
different repeater stations between New
York and Pittsburgh: F. B. ANnpErson,
F. A. Brooks, H. C. FLemine, H. K. Krist,
O. H. Loynes, J. C. Lozier, J. T. O'Leary,
E. H. Perkins, W. H. Tipp, A. C. Vetta
and H. A. WENK.

J. A. Hatt and E. B. Cave appeared be-
fore the Board of Appeals at the Patent
Office relative to applications for patent.

THE LABORATORIES were represented in
interference proceedings at the Patent
Office by B. H. Jackson before the Ex-
aminer of Interferences and by H. S. Wertz
before the Primary Examiner.

Durinc Octoser, G. T. Morris, J. W.
ScuMieED, H. O. Wricut and G. F. HEver-
MAN were at the Patent Office in Washington

J. W. Scumiep and W. F.
Simpson were in Cleveland
during October relative to
patent matters.

H. P. Franz made several
trips to Washington in con-
nection with the Government
regulations on the export of
patent and technical data.

On Novemser 13 Dr. L. D.
Bristol, Health Director, and
Miss T. E. Boden, Supervisor
of Health Education of the
American Telephone and Tele-
graph Company, and C. R.
Kendall, Supervisor of Safety
Methods and First Aid Train-
ing of the New York Tele-
phone Company, attended the
Laboratories’ Women’s First

Aid Class conducted by L.E. |
Coon to observe the methods ©
of training used by the Lab-
oratories. These individuals
will supervise First Aid train-
ing in their respective com-
panies where the Standard
Course of the American Red
Cross will replace shortly the
former Bell System First Aid
and Health Course.

G. B. THomas and R. A.
DELLER attended the Ninth
Annual meeting of the Engi-
neers’ Council for Profes-
sional Development held in
New York City on October 30.

Mr. Deller has been
elected to membership of the Eastern
College Personnel Officers Association. Dur-
ing the latter part of October he visited a
number of universities and the headquarters
of several of the Operating Companies in the
Middle West on matters pertaining to cur-
rent employment needs and on the 1942
program covering the employment of tech-
nically trained men.

Tuomas Brown, a member of the speci-
fications group of the Transmission Appa-
ratus Development Department, died on
November 7. Before he joined the Bell
System in 1930 he had spent nine years on
installation work for the Service Main-
tenance Company, as a draftsman with
Gibbs and Hill, and as a specification writer
with Rainbow Light, Incorporated. During
this time he took evening courses at Cooper
Union from which he received his B.S. de-
gree in 1926.

Mr. Brown entered the Specifications De-
partment of the Apparatus Development
Department in 1930 and for several years
was engaged in writing specifications on
many types of apparatus including sound
picture apparatus and telephone main-
tenance tools. Since 1937 he specialized in
electrical indicating instruments and volt-
meter relays. This work involved consulta-
tion with project engineers and suppliers and
making recommendations on the selection of
suitable meters and relays for telephone and
radio equipment and, more recently, on
similar apparatus for defense projects.

Wa ter S. Hayrorp of the Outside Plant
Department died on October 21. Mr. Hay-
ford was graduated by Northwestern Uni-
versity with a B.S. degree in 1918 and
received a C.E. degree from the same Uni-
versity in 1921. From December, 1917, to
September, 1919, he was with the Taylor
Instrument Company. He joined the Engi-
neering Department of the Western Electric
Company in 1921 and for the next seven
years was with the metals division of the
Materials Standards Department. During
this time he was responsible for the develop-
ment of mechanical test methods which have
since been adopted through the American
Society for Testing Materials as national
standards for the control of such properties
as hardness, standard tension test methods
for thin sheet metals including the design of
the specimen, fatigue-testing machinery and
specimens, and the development of a reverse
bend testing machine.

Since 1928, when Mr. Hayford transferred
to the Outside Plant Development Depart-
ment, he had been engaged continuously
with the development of outside plant tools.
He conceived the idea of a sleeve-rolling tool
for joining line wires and was responsible for
the detailed development work along this
line over a period of several years. He also
had much to do with laboratory studies of
linemen’s climbers, these studies resulting in
considerably improved design from the
standpoint of service life.

tion and maintenance and similar tools for
cable construction and maintenance, both
aerial and underground. He was an expert on
the testing of the hardness of metals and
acted as a consultant on practically all such
measurements made in connection with
outside plant development studies.

L. E. Coon attended the National Safety
Congress held in Chicago from October 5 to
10. The keynote of the meetings was He/p
Defense—Stop Accidents.

R. Linstey SHEPHERD, at a meeting of
the Young Peoples Association of Christ
Church, Short Hills, N. J., discussed the
work of the Laboratories and demonstrated
the Mirrophone.

TRANSMISSION measurements on type-K
carrier systems between Chicago and Joplin
were made by a group of Laboratories engi-

neers during October. Participating in the
tests were A. L. Bonner, F. A. Brooks
L. L. GLezen, L. C. Roserts, H. A. Wenx,
and S. B. Wricut. Mr. Goetz and Mr.
Reichel, of the Long Lines Engineering De-
partment in New York, and various mem.
bers of the Long Lines Plant Department in
the Chicago and St. Louis areas also partici-
pated in this work.

In THE SEPTEMBER 27 issue of Nature
(London) appear two reviews of articles
published in the July issue of the Recorp;
Sound-Integrating Machine and Bell Tele-
phone Laboratories Lecture Equipment.

A. F. Gitson is now Purchase Engineer of
the Plant Department in charge of outside
shop work. K. G. Compton has been trans-
ferred to Whippany where he will act for
the Plant Department as Codrdinator of
Shop Work.

GeorcE Dosson has been transferred to
the Plant Department where he will be in
charge of Order Analysis and Shop Schedules.
F. KEELING is now associated with Mr.
Dobson with responsibility for procurement
of materials and apparatus required for De-
velopment Shop Work.

D. J. HEnprick and the plant engineering
and drafting group have been transferred
to the Plant Occupancy Department.

THIS YEAR many persons are planning to.
give at least part of their gifts in the form
of Defense Savings Bonds and Stamps.
Stamps, with values ranging up to $5
apiece, may be bought at post offices, banks
and savings and loan associations.

To those who can spend $18.75 for one
gift, a Series “E”’ Defense Savings Bond is
ideal. It increases regularly in value until
at its maturity date, ten years hence, it can
be redeemed for $25 or one-third more than
you paid. Other Bonds in the Defense series
are priced all the way up to $1,000 each, and
have corresponding increases in value.

between Stevens Point, Wis-
consin, and Minneapolis. It forms one
of a series of broad-band carrier sys-
tems that have assumed particular
importance with the steadily increas-
ing demands for telephone service
accompanying the rapid expansion of
national defense production. Of these
broad-band systems the K and the J,
as well as a forerunner of the present
coaxial system, have already been
described in the Recorp.* The new
coaxial system, known as the type-Li
carrier system, far surpasses all the
others in the number of channels it
provides—480 in a complete system.
In the installation between Stevens
Point and Minneapolis only a small
part of the full capability of the sys-

tem is utilized at present, but addi-
tional channels may be added from
time to time as desired.

Like other broad-band systems, the
type-L1 system uses sets of twelve
voice channels to form a channel bank.
Each of the twelve voice channels of
the set is modulated by a separate
carrier, and after modulation, the
twelve channels lie in the frequency
band from 60 to 108 ke. Since there
are 480 channels in a complete Li
system, there will be forty of these
channel banks, but only twelve chan-
nel carriers are required in the system
since all channel banks occupy the
same frequency band after channel
modulation.

Following the channel modulation,
which forms a bank from each twelve
channels, there is a second, or group,
modulation that raises these 12-chan-
nel banks in sets of five to form a

6o-channel bank occupying the fre-
quency range from 312 to 552 kc.
Only five group carriers are required
for this second modulation since all
groups of 60 channels that are in-
volved occupy the same frequency
band after group modulation.

The forty banks of twelve channels
are thus formed into eight groups of
60 channels. Since these groups oc-
cupy the same frequency range at the
output of the modulators, they cannot
be placed directly on the line. A third
modulation, or super-grouping, is
therefore provided to produce eight
super-groups, each occupying a differ-
ent frequency band. After this super-
group modulation, the eight super-
groups occupy adjacent portions of
the frequency band from 68 to 2044
ke. This scheme of modulation is
indicated schematically in Figure 1.

It will be noticed that as trans-
mitted over the coaxial cable, the
second super-group occupies the fre-
quency band from 312 to 552 kc,
which is the band occupied by all the
60-channel groups after group modu-
lation. For this super-group therefore
no third modulation is required. Since
only 48 channels were to comprise the
initial installation of the system be-
tween Stevens Point and Minneapolis,

it was possible to avoid the necessity
of a third modulation by using 48
channels which are in the same 6p.
channel bank. Without further modu-
lation it could then be placed directly
on the line, where it would occupy the
No. 2 super-group position of the
complete system. This greatly facili-
tated the completion of the new in-
stallation since it was unnecessary to
provide either the super-group carrier
supply or any of the super-group
modulating equipment. The 48 chan-
nels, of course, comprise only 4 groups
and thus the super-group they form is
short of completeness by one group.
It is expected that this fifth group will
be added shortly.

group frequencies, the separation of
the desired sideband from the carrier
and the other sideband is accom-
plished with a comparatively wide
band filter giving low distortion in the
band. With the L system, on the
other hand, five banks are placed side
by side to form a 60-
channel group, and it

ment that may require maintenance.
The cable is provided with four co-
axial units, but only two are required
for a complete L system—one for each
direction of transmission. The other
pair of coaxial units, with spare re-
peaters at each repeater point, are held

parallel such wide band
tion in adjacent banks | wai
due to overlapping |
bands. This difficulty | [ | nae
is avoided by connect- FILTER RANGE (ODD GROUPS) !
ing the filters of odd-_! | | | |

gether; and similarly
those of the even-num-
bered banks. These two
sets of groups are then
combined through a hybrid coil so
that both sets supply input to the
line, but neither interferes with the
other. This arrangement is indicated
in Figure 2. Here the frequency
boundaries of the five banks forming
the group are indicated by vertical
dashed lines, and the approximate
filter range for the even bands is
shown above, and the range for the
odd bands below.

Group modulation in the L system
also differs from that in the J in the
amount of apparatus required. While
the J system transmits only one group
in each direction, the L system trans-
mits forty. Another difference arises
indirectly because of the much larger
number of channels handled by the L
system. When 40 groups are handled
by a single system, it is desirable to
take greater precautions to insure
continuity of service than when only
one group is involved. As a result the
L system has been designed with
liberal provisions for replacing equip-

Fig. 2—Frequency allocation and filtering arrangements for
the five groups of each super-group

Duplication of facilities is provided
also in the group terminal equipment.
For each group, the modulating equip-
ment includes a_ band-elimination
filter to remove any vestige of the
g2-kc channel carrier (which is rein-
troduced as a separate pilot), a group
modulator, and a band-pass filter to
pass the desired sideband. In the com-
plete system, there will be five of
these sets of apparatus and a common
amplifier for each of the eight group
banks. One or more of these group
banks is provided as a spare, and is
arranged so that it can be substi-
tuted for any of the regular sets on a
moment’s notice. On the receiving
side of the circuit, there will also be
provided one or more spare receiving
group banks.

This provision of spare equipment
will be carried over into the super-
group modulating equipment, but at
the present time there is no super-

group modulation for the Stevens
Point system. No spare channel mod-
ulating equipment is provided on an
immediate transfer basis, since the
majority of the equipment is indi-
vidual to a single channel, and an
interruption to a single channel of this
coaxial system is not so serious as
an interruption in other parts of the
circuit common to more channels.

To facilitate substitution of spare
equipment when maintenance work is
required, the spare and regular cir-
cuits are connected together through
hybrid coils on either their input or
output sides. The arrangement is in-
dicated in Figure 3. The outputs of
the channel modulators in the trans-
mitting side are connected to the
regular and spare group modulating
equipment through the hybrid coil

A.” Also, the outputs of the regular
and spare super-group modulatin
equipments, when installed, will be
associated through the hybrid coil
marked “ss,” and the output of this
hybrid coil is supplied to the regular
and spare coaxial units through the
hybrid coil ‘“‘c.”” With this arrange-
ment the spare group modulating
equipment may be energized at its
input without disturbing regular trans-
mission. When the outputs are first
paralleled, and then interchanged,
there is a slight rise in transmission
during the parallel stage. The spare
group modulating equipment has jacks
at both input and output sides so that
it may be patched in place of any of
the regular group equipments.

FUTURE
LOW-PASS SUPER-GROUP TERMINAL
FILTERS MODULATORS REPEATERS
ge
t REGULAR
B H
88 HYBRID GROUP
| SPARE
NAA ba
92-KC Y
MONITOR
LOW-PASS BAND-PASS SUPPLY
FILTERS ; FILTERS
FUTURE
r SUPER-GROUP
Ze Pieter SWITCHING
25 REGULAR UNITY
t REGULAR

Fig. 3—Schematic diagram of terminal equipment showing provisions for substituting
Spare equipment in order to facilitate maintenance work

system, no super-group modulating
equipment is shown since none is re-
quired. In a complete system, this
super-group modulating equipment
will appear between the low-pass
filter at the output of the group modu-
lating equipment and
the “B” hybrid coil.
Spare group modulat-
ing equipment will also
be provided, and there
may be a substitution
of spare group equip-
ment without the sub-
stitution of spare
super-group equip-
ment, and vice versa.
For this reason the
patching connection is
shown going from the
output of the spare
group modulating
equipment to the upper
branch, where the
regular super-group
modulating equipment
would appear in a
complete system.

On the receiving end
of the line, the ar-
rangement is in gen-
eral the same. In place
of the ‘“‘c” hybrid coil,
however, there is a switching unit so
that transmission will take place over
only one of the coaxial units at a time.
No hybrid coil is used between the
group and channel demodulating
equipments. The substitution of spare
equipment at this point is made by
patching cords.

All patching for substituting the
spare for the regular equipment, as
well as all transmission measuring and
testing, is done at patching bays as
shown in the photograph at the head
of this article and in more detail in
Figure 4. These bays are arranged so

that jacks for later additions to the
system may be added in orderly
fashion. The bay at the right contains
jacks associated with the transmitting
side of the circuit; the bay in the
center, those associated with the re-

ceiving side; and the bay at the left,
those for transmission testing while
the system is in service.

Following J and K system prac-
tice,* the L system derives all its
carriers from a single 4-kc source.
The arrangement provided for the
Stevens Point installation is shown in
Figure 5. Duplicate carrier generators
are employed and they supply various
groups of carriers through hybrid
coils so that on failure of one gener-
ator the load may be carried by the
other immediately. One hybrid sup-
~ *ReEcorp, May, 1938, p. 315.

plies the carriers for the odd channel
modulators, and another for the even.
In addition, there is a hybrid for each
of the five group carriers. Amplifica-
tion is required for these group car-
riers, and duplicate amplifiers, sup-
plied from the two branches of the
hybrid, are multipled at their out-
puts to supply the carriers. For a
complete L system, a 124-kc carrier
derived from this circuit will be sup-
plied to a harmonic producer to ob-
tain the super-group carriers.

Besides the modulating carriers,
four pilot frequencies, 64, 556, 2064,
and 3096 kc, are required for regula-
tion, and a pilot of 92 kc is employed
to give an overall test of circuit con-
tinuity of each group. This latter
pilot—the continued use of which will
depend on its maintenance value—is
introduced into each group just ahead
of the group modulators, and is taken
off at the output of the amplifiers that
follow the group demodulators at the
receiving end. Both 64 and 92 kc are
channel-carrier frequencies, and the
pilots of these frequencies are taken
from the channel carrier supply. The
556-kc pilot is obtained by adding in

a modulator the channel carrier fre-
quency of 88 kc to the group carrier
frequency of 468 kc. To secure the
2064. and 3096-kc pilots, a frequency
of 516 kc is taken from one of the
group-carrier supplies and_ passed
through a harmonic producer. The
fourth and sixth harmonics provide
the desired pilots.

The stability required of the basic
4-ke source of the carriers and pilots
depends directly on the highest fre-
quency to be transmitted over the
line, and for a complete Lr system,
40 times greater stability is required
than for the K system. For the limited
frequency range utilized at present
between Stevens Point and Minne-
apolis, however, a stability only ten
times greater than that of the K
system is required. The 4-kc oscillator
and harmonic generator circuit pro-
vided at Minneapolis and Stevens.
Point is the same as for the K system
except the tuning forks controlling the
frequency were selected for particu-
larly good temperature coefficients. As
the system grows the 4-kc oscillator
will be replaced by even more stable
crystal-controlled oscillators.

EQUALIZERS
COMMON CHANNEL CARRIER SUPPLY GROUP CARRIER SUPPLY
TO CHANNEL] MODULATORS
AND DEIMODULATORS \, [420] | 5i6| | FILTERS
CARRIER (EVEN) (oDD)
NETWORK -{72] | HYBRID DEMODULATORS
(4 GROUPS)
HYBRID NET HYBRID
CIRCUIT WORK DISTRIBUTING
CIRCUIT
GENERATOR FILTERS FILTERS
[420] | 516 | | S64] FILTERS

plied to a vacuum tube
arranged in a suitable circuit, the
output will include not only the two
frequencies of the input but an infinite
series of combination frequencies of
which the most important are the
sum and the difference of the two
input frequencies. This process is
called modulation. It arises from the
non-linear relationship between input
voltage and output current of the
vacuum tube. Any circuit device with
a similar non-linear characteristic is
capable of modulating. It is the pro-
duction of these sum and difference
frequencies that makes possible all
carrier telegraph and telephone com-
munication and practically all radio
transmission.

Copper oxide varistors have non-
linear characteristics somewhat simi-
lar to those of a vacuum tube and they
also may serve as modulators. Their
small size, long life, and low original
cost and maintenance as compared to
vacuum tubes make their use highly
desirable, and at least as early as 1927
they were being tried as modulators in
carrier systems. Along with these ex-
periments, development work was
being continued on the copper oxide
varistors themselves, and both devel-
opments were crowned with consider-
able success. The first commercial use
of copper oxide modulators was in
the type-G carrier system, but since
then they have been used with the
H, J, K, and Cs carrier systems.

When used as modulators in carrier
systems, four or more sets of copper
oxide varistors are arranged in a
square network like a Wheatstone
bridge, and usually assembled in a
small metal case. The modulator used
for the type-K carrier system is shown
above. The method of connecting the
modulator into the circuit varies with
the type of system, since the type of
connection affects the output com-
ponents. In the G1 system, for ex-
ample, the connection is such that the
carrier is transmitted, while with the
Cs, K, and J systems, the connection
is such as to eliminate the carrier. An
indefinite number of circuit configura-
tions are possible, and five are already
in use.

Another of the advantages of the
copper oxide modulator is that it
transmits signals in either direction.
The same unit may thus be used
either as a modulator or demodulator.
The small size of the units permits the
modulating and demodulating units
to be mounted on the same panel, and
when this is done the combined unit is
called a modem.

able for a number of years to
enable telephone subscribers to con-
nect to any of several lines, to transfer
calls, signal extensions, or perform
any of a number of switching opera-
tions that would make their tele-
phone service more useful. With the
advent of the combined telephone
set, which includes the ringer and
other equipment in the base of the
telephone, the 1A key telephone sys-
tem* was developed to provide a large
number of switching arrangements,
all controlled by keys mounted in the
telephone base. Such an arrangement
greatly improves the appearance of
the station equipment by avoiding
separately mounted keys and ringers,
and is more convenient to use because
of the close association of the keys
with the telephone itself. Ordinary
~ *REcorD, June, 1940, PD. 315.

telephone keys, however, are far too
large to use in the restricted space of a
handset base. It was necessary, there-
fore, to develop keys that would fit in
the shallow clearance of the base.

To reduce the vertical space re-
quired by the keys, the contact springs -
were made L-shape, the contact ends
extending horizontally and the termi-
nal ends extending vertically upward
with small soldering lugs projecting
horizontally backward. A further re-
duction in the vertical space required
was obtained by using a conical spring
in place of the usual cylindrical re-
storing spring. With a cylindrical
spring, the minimum height is the
number of turns times the diameter of
the wire, while with a conical spring
the turns lie within one another so
that the minimum height becomes
the diameter of the wire alone. In
this way the depth required is less
than half that needed for the usual

type of key. A maximum of nine con-
tact springs may be assembled in
each unit, and such an assembly is
shown in Figure 1. The contact
springs are operated by a plunger
with a hard-rubber tip that is pushed
down between the two lipped springs.

It was desired to mount as many
as six of these assemblies in the base
of a telephone set, and thus horizontal
as well as vertical space was at a
premium. The springs themselves
were therefore made of lighter ma-
terial than that used for ordinary
keys, and the amount of travel be-
tween operated and unoperated posi-
tions was reduced. To insure adequate
contact pressure and sequence under
these conditions, a strip of insulating
material isincluded in thespring pile-up
to pre-position the springs. This strip,
evident near the front ends of the
springs in Figure 1, is slotted to re-
ceive projections from the springs. It
permits each stationary spring to be
given an initial tension so that only a
slight displacement of the moving
spring is needed to build up adequate
contact pressure. The slots also fix the
unoperated positions of the stationary
springs so that the desired operational
sequence may be more readily ob-
tained. Spacing strips of this type are

commonly used with relays, where the
amount of motion is also strictly
limited, but they are not ordinarily
used with keys.

One of the complete keys is shown
in Figure 2. The spring assemblies are
fastened to a brass mounting plate,
and two steel brackets are used to at-
tach to the base of the handset both
the mounting plate and an insulating

plate that serves as a terminal block
for both the keys and the handset.
The front edge of the brass plate is
drilled for the plungers that operate
the keys, and a narrower brass strip is
held beneath the mounting plate and
drilled for the hard-
rubber tip of the
plungers. A metal
washer is fastened to
the plunger just above
the hard-rubber tip,
and between this
washer and the lower
brass strip is the coni-
cal restoring spring
that holds the plunger
in its normal or “up”
position. A third strip,
called a slide plate, is
mounted so as to be

just above the washers when the
plungers are in the normal “‘up”’ posi-
tion. This plate is drilled for the
plungers with an oversize hole, and is
free to move horizontally in the
direction of its length. It provides the
locking and releasing feature com-
monly used with mechanically locking
keys. Most of the spring assemblies
are used to associate the handset with

Fig. 3—Diagrammatic representation of the
locking bar and the pawl mechanism for the
hold button

one or another of a group o: lines, and
by the use of the slide plate, the de.
pression of any one of the “line” keys
will release any other, and will lock
itself in.

This slide plate is slotted at each
end for the two end posts holding the
plates in place, and is held in one ex-
treme position by a coiled spring
fastened to the top plate. Each plunger
has a flat-topped cone-shaped section
just above the hole, and as the
plunger is depressed, the cone forces
the slide plate to one side until the
top of the cone is below the slide
plate, which then snaps back above
the shoulder of the cone and holds the
plunger depressed. When another
plunger is operated, its cone will push
the slide plate to one side, and the
key already operated will release just
before the newly operated key is
locked. These actions are shown in
lines 2 and 3 of Figure 3.

With the 14 key system it was de-
sired to provide a common holding
key so that a call on any line could be
held, and the handset disconnected
from that line and connected to an-
other. This requires that there be an
appreciable interval between the clos-
ing of the contacts of the “hold”
button and the releasing of the line
button operated. With this slide plate
construction, however, it is evident
that the releasing of the line would
follow almost immediately the closing
of the holding contact. To secure the
time interval desired, the cone on the
“hold” plunger is inverted so that its
flat shoulder faces down, and in the
slide plate the edge of the hole that
normally rests against the plunger is
cut out and fitted with a pawl. This is
tipped down by the shoulder of the
cone when the plunger is depressed,
and then is snapped back by a flat
spring as the shoulder passes beneath

it. The arrangement is shown in lines
4and 5 of Figure 3. When the “hold”
button is depressed, the slide plate is
not moved because of the deflection of
the pawl. When the button is re-
leased, however, the slide plate is de-
flected by the upward motion of the
cone, and the operated “‘line” button
is released. In this way the “line”
button is not released until an ap-
preciable interval after the “hold”
contact has been made.

The key plungers shown in Figure 2
are operated by insulating buttons
that project through the handset
base. If these buttons were rigidly at-
tached to the plungers, either the
manufacturing tolerances would have
to be very small, or the holes in the
base would have to be considerably
larger than the plungers to allow for
manufacturing variations. This is
avoided by mounting hard-rubber
buttons loosely in the base of the
handset, and giving them a flanged
base that is somewhat larger than the
tops of the plungers. The arrangement
is shown in Figure 4. With such a
design, accurate alignment of plunger
and button is not necessary.

the “turn” key, one of which is shown
at the extreme right of Figure 2. A
button of this type is useful for such
operations as transferring a line or
cutting off an extension or ringer.
Two standard multi-button keys
have been provided for the 14 system:

four spring assemblies and the latter
six, but the keys of either type are
available in a variety of spring combi-
nations. Both units mount in the large
telephone set used primarily for the
1A key system.

For stations of the 1a system that
have access to only one or two lines,
the smaller telephone set may be
used. In this smaller telephone set, the
only room available for a key is a
restricted space between the ringer
magnet and the wall of the housing.
To fit in this space, the very small key
shown in Figure § was developed.
Known as the 559, it is a combination
turn and push button. One set of
springs is operated when the button is
turned, and another set—usually em-
ployed for signaling—when the but-

ton is pressed. The “press”? contact
may be made with the button turned
in either direction. The button of this
key is fastened directly to the plunger,
and alignment is provided by using
slots instead of holes for the mounting
screws. Shoulders on the mounting
screws permit the key assembly to be
firmly held while still permitting a
small amount of lateral motion in any
direction. This key may be used for
picking up either of the lines associ-

SINCE PRIVATE BRANCH EXCHANGES
and key telephone systems have been
ALBERT TrapDup’s life work, he was very
well prepared to undertake the codrdina-
tion of development work on the tele-
phone system for the Air Corps’ Infor-
mation Centers. Entering A. T. & T. in
1920, Mr. Tradup was assigned to formu-
lating the electrical, mechanical and
physical requirements for PBX switch-
boards. Since the consolidation of the
D. and R. with the Laboratories in 1934,
he has continued that work in the Sys-
tems Development Department. He was
graduated by the University of South
Dakota in 1915 with a B.S. degree, when
he entered the Northwestern Bell.

ated with the telephone set, for trans-
ferring a call to an extension, for cut-
ting off an extension or ringer, or for
signaling.

With these three types of keys, the
IA system can provide almost any
form of switching service desired.
The keys are ordered to meet the
Operating requirements, and all the
connections for the telephone set are
made on the terminal block of the key
when the system is installed.

CLINTON SHAFER, JR., joined the Lab-
oratories in 1925, shortly after receiving
an M.E. degree from Stevens Institute of
Technology. He started in the Inspection
Engineering Department and was trans-
ferred to the Outside Plant Development
Department when it was organized in
1927. From then until 1940 he was engaged
principally in development work on rub-
ber-covered wire. Since then he has been
engaged in outside plant facilities studies.

R. E. Crane graduated
from the Harvard Engineer-
ing School in 1923 and im-
mediately joined the Engi-
neering Department of the
Western Electric Company.
He has been engaged since
that time in development
work on carrier telephone
systems. For the last several

years he has been in charge of a group
which has been concerned with the termi-
nals of broad-band carrier systems, prin-
cipally those for application to voice-
frequency and coaxial cables.

E. C. Matruews joined the Engineer-
ing Department of the Western Electric
Company in 1914, and for five years was
engaged as a draftsman in the develop-
ment of dial system apparatus. During
this time he attended the Newark Tech-
nical School from which he graduated in

Bound copies of Volume 19 of the Recorp (September, 1940, to
August, 1941) are now available — $2.75, foreign postage 25
cents additional. Remittances should be addressed to Bell Lab-
oratories Record, 463 West Street, New York. A separate index
to Volume 19 is now available and may be obtained upon request

System advertisement repro-
duced on the opposite page. To indi-
cate the extensive coverage of the
type-K and other new broad-band
carrier systems, the routes over which
they are expected to be in operation
at the end of this year and at the end
of next are indicated on the map
below. The number of systems in use
or projected along routes shown varies
considerably. Only five systems, for
example, are planned between St.

Louis and Joplin by the end of this
year, as compared with thirty-four
between New York and Washington.
The present tentative view, however,
is that by the end of next year—De-
cember thirty-first, 1942—the num-
ber in the section between Joplin and
St. Louis will be more than quadru-
pled, while in the section between New
York and Washington the number will
be nearly tripled. It is expected that
some two and a half million circuit
miles of broad-band carrier facilities
will be available by the end of 1942.

LE
AUSTINA
BY PROPOSED san ORLEANS
DEC.31, 1941 FOR 1942 ANTONIO “Stony, TAMPA\O
K CARRIER S\PALM BEACH
J CARRIER
COAXIAL

Bell Laboratories Record  1941-12: Vol 20 Iss 4