| ==Phrack Inc.== | |
| Volume Two, Issue 24, File 6 of 13 | |
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| [] [] | |
| [] Glossary Terminology [] | |
| [] For Enhanced 911 Services [] | |
| [] [] | |
| [] By The Eavesdropper [] | |
| [] [] | |
| [] March, 1988 [] | |
| [] [] | |
| [][][][][][][][][][][][][][][][][][][][][][][][][][][][][][] | |
| E911 - Enhanced 911: Features available include selective routing, selective | |
| transfer, fixed transfer, alternate routing, default routing, Automatic | |
| Number Display, Automatic Location Identification, night service, | |
| default routing, call detail record. | |
| End Office - Telephone central office which provides dial tone to the | |
| subscriber calling 911. The "end office" provides ANI (Automatic | |
| Number Identification) to the tandem office. | |
| Tandem Office - Telephone central office which serves as a tandem (or hub) for | |
| all 911 calls. Must be a 1AESS type of central office. The | |
| tandem office translations contain the TN/ESN relationships | |
| which route the 911 call to the proper SAP. The tandem office | |
| looks up the ANI (TN) that it receives from the end office and | |
| finds the ESN (routing information) which corresponds to a | |
| seven digit number ringing in at a PSAP. | |
| PSAP - Public Safety Answering Point, usually the police, fire and/or rescue | |
| groups as determined by the local municipalities. A "ringin" will not | |
| have ANI or ALI capabilities, but just receives calls or transferred | |
| calls from another PSAP. | |
| ESN - Emergency Service Number (XXX) that is assigned to the subscriber's | |
| telephone number in the tandem office translations The ESN represents a | |
| seven digit number by which the tandem office routes the call to the | |
| proper PSAP. PSAPs with ALI capabilities also receive a display of the | |
| ESN information which shows which police, fire and rescue agency serves | |
| the telephone number calling 911. An ESN is a unique combination of | |
| police, fire, and rescue service for purposes of routing the E911 call. | |
| ANI - Automatic Number Identification corresponds to the subscriber's seven | |
| digit telephone number. The ANI displays at the PSAP on the digital ANI | |
| display console. | |
| ALI - Automatic Location Identification provides for an address display of the | |
| subscriber calling 911. With ALI, the PSAP receives the ANI display and | |
| an ALI display on a screen. The ALI display includes the subscriber's | |
| address, community, state, type of service and if a business, the name of | |
| the business. The PSAP will also get a display of the associated ESN | |
| information (police, fire, rescue). | |
| Selective Routing - The capability to route a call to the particular PSAP | |
| serving the address associated with the TN making the 911 | |
| call. Selective routing is achieved by building TN/ESN | |
| translations in the tandem central office. These | |
| translations are driven by the E911 data base which assigns | |
| the ESN to each telephone number based on the customer's | |
| address. Service order activity keeps the E911 data base | |
| updated. The E911 data base, in turn, generates recent | |
| change to the tandem office (through the SCC or RCMAC) to | |
| update the TN/ESN translations in the tandem data base. | |
| Selective Transfer - Provides the PSAP with the ability to transfer the | |
| incoming 911 call to a fire or rescue service for the | |
| particular number calling 911 by pushing one button for | |
| fire or rescue. For example, if an incoming 911 call was | |
| reporting a fire, the PSAP operator would push the fire | |
| button on the ANI console; the call would go back to the | |
| tandem office, do a lookup for the seven digit number | |
| associated with fire department, for the ESN assigned to | |
| the calling TN, and automatically route the call to that | |
| fire department. This differs from "fixed" transfer which | |
| routes every call to the same fire or rescue number | |
| whenever the fire or rescue button is pushed. The PSAP | |
| equipment is optioned to provide either fixed or selective | |
| transfer capabilities. | |
| Alternate Routing - Alternate routing provides for a predetermined routing for | |
| 911 calls when the tandem office is unable to route the | |
| calls over the 911 trunks for a particular PSAP due to | |
| troubles or all trunks busy. | |
| Default Routing - Provides for routing of 911 calls when there is an ANI | |
| failure. The call will be routed to the "default" ESN | |
| associated with the he NNX the caller is calling from. | |
| Default ESNs are preassigned in translations and are usually | |
| the predominant ESN for a given wire center. | |
| Night Service - Night service works the same as alternate routing in that the | |
| calls coming into a given PSAP will automatically be routed to | |
| another preset PSAP when all trunks are made busy due to the | |
| PSAP closing down for the night. | |
| Call Detail Record - When the 911 call is terminated by the PSAP operator, the | |
| ANI will automatically print-out on the teletypewriter | |
| located at the PSAP. The printout will contain the time | |
| the call came into the PSAP, the time it was picked up by | |
| an operator, the operator number, the time the call was | |
| transferred, if applicable, the time the call was | |
| terminated and the trunk group number associated with the | |
| call. Printouts of the ALI display are now also | |
| available, if the PSAP has purchased the required | |
| equipment. | |
| ANI Failure - Failure of the end office to identify the call and provide the | |
| ANI (telephone number) to the tandem office; or, an ANI failure | |
| between the tandem office and the PSAP. | |
| Misroute - Any condition that results in the 911 call going to the wrong PSAP. | |
| A call can be misrouted if the ESN and associated routing | |
| information are incorrect in the E911 data base and/or tandem data | |
| base. A call can also be misrouted if the call is an ANI failure, | |
| which automatically default routes. | |
| Anonymous Call - If a subscriber misdials and dials the seven digit number | |
| associated with the PSAP position, they will come in direct | |
| and ANI display as 911-0000 which will ALI as an anonymous | |
| call. The seven digit numbers associated with the PSAP | |
| positions are not published even to the PSAPs. | |
| Spurious 911 Call - Occasionally, the PSAP will get a call that is not | |
| associated with a subscriber dialing 911 for an emergency. | |
| It could be a subscriber who has not dialed 911, but is | |
| dialing another number, or has just picked up their phone | |
| and was connected with the PSAP. These problems are | |
| equipment related, particularly when the calls originate | |
| from electromechanical or step by step offices, and are | |
| reported by the E911 Center to Network Operations upon | |
| receipt of the PSAP inquiry reporting the trouble. The | |
| PSAP may get a call and no one is there; if they call the | |
| number back, the number may be disconnected or no one home. | |
| Again these are network troubles and must be investigated. | |
| Cordless telephones can also generate "spurious" calls in | |
| to the PSAPs. Generally, the PSAP will hear conversation | |
| on the line, but the subscribers are not calling 911. The | |
| PSAP may report spurious calls to to repair if they become | |
| bothersome, for example, the same number ringing in | |
| continually. | |
| No Displays - A condition where the PSAP ALI display screen is blank. This | |
| type of trouble should be reported immediately to the SSC/MAC. | |
| If all screens at the PSAP are blank, it is an indication that | |
| the problem is in the circuits from the PSAP to the E911 | |
| computer. If more than one PSAP is experiencing no display, it | |
| may be a problem with the Node computer or the E911 computer. | |
| The SSC/MAC should contact the MMOC to determine the health of | |
| the HOST computer. | |
| Record Not Found - If the host computer is unable to do a look up on a given | |
| ANI request from the PSAP, it will forward a Record Not | |
| Found message to the PSA ALI screen. This is caused by | |
| service order activity for a given subscriber not being | |
| processed into the E911 data base, or HOST computer system | |
| problems whereby the record cannot be accessed at that point | |
| in time. | |
| No ANI - This condition means the PSAP received a call, but no telephone number | |
| displayed on the ANI console. The PSAP should report this condition | |
| immediately to the SSC/MAC. | |
| PSAP Not Receiving Calls - If a PSAP cannot receive calls or request retrievals | |
| from the E911 host computer, i.e., cable cut, the | |
| calls into that PSAP must be rerouted to another | |
| PSAP. The Switching Control Center must be notified | |
| to reroute the calls in the tandem office E911 | |
| translations. | |
| MSAG - Master Street Address Guide. The MSAG ledgers are controlled by the | |
| municipality which has purchased the E911 ALI service, in that they | |
| assign which police, fire or rescue agency will serve a given street and | |
| number range. They do this by assigning an ESN to each street range, | |
| odd, even, community that is populated in the county or municipality | |
| served. These MSAGs are then used as a filter for service order | |
| activity into the E911 computer data base to assign ESNs to individual | |
| TN records. This insures that each customer will be routed to the | |
| correct agency for their particular address. In a non-ALI County, TAR | |
| codes are used by the Telephone company to assign ESNs to service | |
| conductivity and the County does not control the ESN assignment. TAR | |
| codes represent the taxing authority for the given subscriber which | |
| should correspond to their police, fire and rescue agencies. The MG | |
| method, of course, is more accurate because it is using the actual | |
| service address of the customer to route the call and provides the | |
| county with more flexibility in assigning fire and rescue district, etc. | |
| The Customer Services E911 Group maintains the E911 computer data base | |
| and interfaces with the County (customer) on all MSAG or data base | |
| activity. | |
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