| ==Phrack Inc.== | |
| Volume Four, Issue Forty-One, File 7 of 13 | |
| How To Build A DMS-10 Switch | |
| by The Cavalier | |
| Society for the Freedom of Information | |
| March 11, 1992 | |
| With the telephone network's complexity growing exponentially as the | |
| decades roll by, it is more important than ever for the telecom enthusiast to | |
| understand the capabilities and function of a typical Central Office (CO) | |
| switch. This text file (condensed from several hundred pages of Northern | |
| Telecom documentation) describes the features and workings of the Digital | |
| Multiplex Switch (DMS)-10 digital network switch, and with more than an average | |
| amount of imagination, you could possibly build your own. | |
| The DMS-10 switch is the "little brother" of the DMS-100 switch, and the | |
| main difference between the two is the line capacity. The DMS line is in | |
| direct competition to AT&T's ESS line (for the experienced folks, the features | |
| covered are the as those included in the NT Software Generic Release 405.20 for | |
| the 400 Series DMS-10 switch). | |
| Table of Contents | |
| ~~~~~~~~~~~~~~~~~ | |
| I. OVERVIEW/CPU HARDWARE SPECS | |
| II. NETWORK SPECS | |
| 1. Network Hardware | |
| 2. Network Software | |
| 3. Advanced Network Services | |
| III. EXTERNAL EQUIPMENT SPECS | |
| 1. Billing Hardware | |
| 2. Recorded Announcement Units | |
| 3. Other Misc. Hardware | |
| IV. MAINTENANCE AND ADMINISTRATION | |
| 1. OAM | |
| 2. Interactive Overlay Software Guide | |
| V. SPEC SHEET | |
| VI. LIMITED GLOSSARY | |
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - | |
| I. OVERVIEW/CPU HARDWARE SPECS | |
| Overview | |
| The DMS-10 switch is capable of handling up to 10,800 lines, and was | |
| designed for suburban business centers, office parks, and rural areas. It can | |
| be installed into a cluster configuration to centralize maintenance and | |
| administration procedures and to increase combined line capacity to 50,000 | |
| lines. It is capable of functioning as an End Office (EO), an Equal Access End | |
| Office (EAEO), and an Access Tandem (AT), and is a known as a Class 5 switch. | |
| It supports up to 3,408 trunks and 16,000 directory numbers. It can outpulse | |
| in DP (Dial Pulse), MF (Multi-Frequency), or DTMF (Dual-Tone Multi-Frequency), | |
| insuring compatibility with new and old switches alike (translation -- the | |
| switch is small, by most standards, but it has massive bounce for the ounce). | |
| Hardware Specifications | |
| The DMS-10 switch itself is a 680x0-based computer with 1 MB of RAM in its | |
| default configuration. The processor and memory are both duplicated; the | |
| backup processor remains in warm standby. The memory system is known as the | |
| n+1 system, meaning that the memory is totally duplicated. | |
| II. NETWORK SPECS | |
| Network Hardware | |
| The DMS-10 network hardware consists mostly of PEs, or Peripheral | |
| Equipment trunk and line packs. The PEs take the incoming analog voice | |
| signals, digitalize them into 8 bit PCM (Pulse Code Modulation) signals, and | |
| feed it into the main transmission matrix section of the switch. There, it is | |
| routed to another trunk or line and converted back into an analog signal for | |
| retransmission over the other side of the call. Note that manipulating voice | |
| in the digital domain allows the signal to be rerouted, monitored, or | |
| retransmitted across the country without any reduction in signal quality as | |
| long as the signals remain in PCM format. <Hint!> | |
| Network Software | |
| The DMS-10 has a variety of software available to meet many customers' | |
| switching needs. A good example of this software is the ability of several | |
| DMS-10 switches to be set up in a cluster (or star configuration, for those of | |
| you familiar with network topologies). In this arrangement, one DMS-10 is set | |
| up as the HSO (Host Switching Office) and up to 16 DMS-10s are set up as SSOs | |
| (Satellite Switching Offices), allowing all billing, maintenance, and | |
| administration to be handled from the HSO. Additionally, all satellites can | |
| function on their own if disconnected from the HSO. | |
| Another feature of the DMS-10's network software are nailed-up | |
| connections, commonly known as loops. The DMS-10 supports up to 48 loops | |
| between any two points. The connections are constantly monitored by the switch | |
| computer, and if any are interrupted, they are re-established. | |
| Meridian Digital Centrex (MDC) is the name given to a group of features | |
| that enable businesses to enjoy the benefits of having PBX (Private Branch | |
| Exchange) equipment by simply making a phone call to the local telco. | |
| Advanced Network Services (ANS) | |
| If the DMS-10 is upgraded with the 400E 32-bit RISC processor, the switch | |
| will be able to handle 12,000 lines, enjoy a speed improvement of 80%, support | |
| a six-fold increase in memory capacity, and, perhaps most importantly, will be | |
| able to run NT's Advanced Network Services software. This software includes | |
| Common Channel Signaling 7 (CCS7), Advanced Meridian Digital Centrex, DMS | |
| SuperNode connectivity, and ISDN. CCS7 is the interswitch signaling protocol | |
| for Signaling System 7, and the concept deserves another text file entirely | |
| (see the New Fone eXpress/NFX articles on SS7). | |
| III. EXTERNAL EQUIPMENT SPECS | |
| Billing Format Specifications | |
| The DMS-10 can record AMA (Automatic Message Accounting) billing data in | |
| either Bellcore or Northern Telecom format, and it can save this data in one of | |
| several ways: | |
| - by saving onto a 9-track 800 BPI (Bits-Per-Inch) density tape drive | |
| called an MTU (Magnetic Tape Unit) | |
| - by saving onto a IOI (Input/Output Interface) pack with a 64 MB SCSI | |
| (Small Computer System Interface) hard drive, and transferring to 1600 | |
| BPI tape drives for periodic transport to the RAO (Regional Accounting | |
| Office) | |
| - by transmitting the data through dial-up or dedicated telephone lines | |
| with the Cook BMC (Billing Media Converter) II, a hard drive system that | |
| will transmit the billing records on request directly to the RAO. The | |
| Cook BMC II supports six different types of transmission formats, listed | |
| below: | |
| * AMATS (BOC) [max speed: 9600 bps] | |
| Call records are stored using the Bellcore AMA format and polled | |
| using the BX.25 protocol. Two polling ports are provided with one | |
| functioning as a backup. | |
| * BIP Compatible [max speed: 9600 bps (2400*4)] | |
| Call records are stored using the Bellcore AMA format and polled | |
| using the HDLC Lap B protocol. Four polling ports are provided | |
| that can function simultaneously for a combined throughput of 9600 | |
| bps. This specification is compatible with GTE's Billing | |
| Intermediate Processor. | |
| * Bellcore AMA w/ BiSync polling [max speed: 9600 bps] | |
| Call records are stored using the Bellcore AMA format and polled | |
| using the IBM BiSync 3780 protocol. One polling port is provided. | |
| This option is intended for operating companies who use independent | |
| data centers or public domain protocols for data processing. | |
| * Bellcore AMA w/ HDLC polling [max speed: 9600 bps] | |
| Call records are stored using the Bellcore AMA format and polled | |
| using the HDLC (High-level Data Link Control) protocol. One port | |
| is provided. | |
| * NT AMA w/ HDLC polling [max speed: 9600 bps] | |
| Call records are stored using the Northern Telecom AMA format and | |
| polled using the HDLC protocol. | |
| * NT AMA w/ BiSync polling [max speed: 4800 bps] | |
| Call records are stored using the Northern Telecom AMA format and | |
| polled using the BiSync protocol. | |
| - by interfacing with AT&T's AMATS (Automatic Message Accounting | |
| Teleprocessing System) | |
| - by interfacing with the Telesciences PDU-20 | |
| All of the above storage-based systems are fully fault-tolerant, and the | |
| polled systems can store already-polled data for re-polling. | |
| Recorded Announcement Units | |
| The DMS-10 system may be interfaced to one or more recorded announcement | |
| units through two-wire E&M trunks. Some units supported include the Northern | |
| Telecom integrated Digital Recorded Announcement Printed Circuit Pack (DRA | |
| PCP), the Cook Digital Announcer or the Audichron IIS System 2E. | |
| The DRA PCP is integrated with the DMS-10 system, as opposed to the Cook | |
| and Audichron units, which are external to the switch itself. It provides | |
| recorded announcements on a plug-in basis and offers the following features: | |
| - Four ports for subscriber access to announcements | |
| - Immediate connection when pack is idle | |
| - Ringback tone when busy until a port is free | |
| - Switch-selectable message lengths (up to 16 seconds) | |
| - Local and remote access available for message recording | |
| - Memory can be optionally battery-backed in case of power loss | |
| - No MDF (Main Distribution Frame) wiring required | |
| Other External Hardware | |
| The DMS-10 can also support the Tellabs 292 Emergency Reporting System, | |
| the NT Model 3703 Local Test Cabinet, and the NT FMT-150 fiber optic | |
| transmission system. More on this stuff later, perhaps. | |
| IV. MAINTENANCE AND ADMINISTRATION | |
| OAM | |
| --- | |
| OAM, or Operations, Administration, and Maintenance functions, are | |
| performed through an on-site maintenance terminal or through a remote | |
| maintenance dial-in connection. The DMS-10 communicates at speeds ranging from | |
| 110 to 9600 baud through the RS-232C port (standard) in ASCII. There can be up | |
| to 16 connections or terminals for maintenance, and security classes may be | |
| assigned to different terminals, so that the terminal can only access the | |
| programs that are necessary for that person's job. The terminals are also | |
| password protected, and bad password attempts result in denied access, user | |
| castration and the detonation of three megatons of on-site TNT. <Just kidding> | |
| The software model for the DMS-10 consists of a core program which loads | |
| overlays for separate management functions. These overlays can be one of two | |
| types: either free-running, which are roughly analogous to daemons on Unix | |
| environments, which are scheduled automatically; or interactive, which | |
| communicate directly with the terminal user. | |
| The major free-running programs are the Control Equipment Diagnostic | |
| (CED), the Network Equipment Diagnostic (NED), the Peripheral Equipment | |
| Diagnostic (PED), and the Digital Equipment Diagnostic (DED). The CED runs | |
| once every 24 hours, and tests the equipment associated with the CPU buses and | |
| the backup CPU. The NED runs whenever it feels like it and scans for faults in | |
| the network and proceeds to deal with them, usually by switching to backup | |
| hardware and initiating alarm sequences. The PED is scheduled when the switch | |
| is installed to run whenever the telco wants it to, and it systematically tests | |
| every single trunk and line connected to that central office (CO). The DED | |
| tests the incoming line equipment that converts analog voice to digital PCM. | |
| Now, for interactive programs (a.k.a. interactive overlays), I'm going to | |
| list all of their codes, just in case one of you gets lucky out there. To | |
| switch to an overlay, type OVLY <overlay>. To switch to a sub-overlay, type | |
| CHG <sub-overlay>. Keep in mind that NT has also installed help systems on | |
| some of their software, accessible by pressing "?" at prompts. Here we go: | |
| Overlay Explanation and Prompting Sequences | |
| ------- ----------------------------------- | |
| ALRM Alarms | |
| ALPT - Alarm scan points | |
| SDPT - Signal distribution points | |
| AMA Automatic Message Accounting | |
| AMA - Automatic Message Accounting | |
| MRTI - Message-rate treatment index | |
| PULS - Message-rate pulsing table | |
| TARE - Tariff table | |
| AREA Area | |
| CO - Central Office Code | |
| HNPA - Home Numbering Plan Area | |
| RC - Rate Center | |
| RTP - Rate Treatment Package | |
| CLI Calling Line Identification | |
| CNFG Configuration Record | |
| ALRM - Alarm System Parameters | |
| AMA - Automatic Message Accounting parameters | |
| BUFF - System Buffers | |
| CCS - Custom Calling Services | |
| CCS7 - Common Channel Signaling No. 7 | |
| CDIG - Circle Digit Translation | |
| CE - Common Equipment Data | |
| CLUS - Cluster data | |
| COTM - Central Office overload call timing | |
| CP - Call processing parameters | |
| CROT - Centralized Automatic Reporting of Trunks | |
| CRTM - Central Office regular call processing timing | |
| CSUS - Centralized Automatic Message Accounting suspension | |
| DLC - Data Link Controller assignment for clusters | |
| E800 - Enhanced 800 Service | |
| FEAT - Features | |
| GCON - Generic Conditions | |
| HMCL - Host message class assignment | |
| IOI - Secondary input/output interface pack(s) | |
| IOSF - Input/Output Shelf Assignment | |
| LCDR - Local Call Detail Recording | |
| LIT - Line Insulation Testing parameters | |
| LOGU - Logical Units Assignments | |
| MOVE - Move Remote Line Concentrating Module | |
| MTCE - Maintenance Parameters | |
| MTU - Magnetic Tape Unit Parameters | |
| OPSM - Operational Measurements | |
| OVLY - Overlay scheduling | |
| PSWD - Password Access | |
| SITE - Site assignments | |
| SSO - Satellite Switching Office Assignments | |
| SUB - Sub Switch | |
| SYS - System parameters | |
| TRB - Periodic trouble status reporting | |
| VERS - Version | |
| CPK Circuit Pack | |
| ACT - AC Testing Definition | |
| DCM - Digital Carrier Module | |
| LPK - Line Concentrating Equipment line packs | |
| PACK - Peripheral Equipment packs | |
| PMS - Peripheral Maintenance System pack | |
| PSHF - Peripheral Equipment Shelf | |
| RMM - Remote Maintenance Module | |
| RMPK - Remote shelf | |
| RSHF - Remote Concentration Line Shelf | |
| SBLN - Standby line | |
| SLC - SLC-96 | |
| SLPK - SLC-96 pack | |
| DN Directory Number | |
| ACDN - Access Directory Number | |
| CRST - Specific Carrier Restricted | |
| ICP - Intercept | |
| RCFA - Remote Call Forwarding appearance | |
| ROTL - Remote Office Test Line | |
| STN - Station Definition | |
| EQA Equal Access | |
| CARR - Carrier Data Items | |
| CC - Country Codes | |
| HUNT Hunting | |
| DNH - Directory Number Hunting | |
| EBS - Enhanced Business Services hunting | |
| KEY - Stop hunt or random make busy hunting | |
| LAN Local Area Network | |
| LAC - LAN Application Controller | |
| LCI - LAN CPU Interface | |
| LSHF - Message LAN Shelf | |
| NET Network | |
| D1PK - DS-1 interface pack (SCM-10S) | |
| 1FAC - Interface packs | |
| LCM - Line Concentrating Module | |
| LCMC - Line Concentrating Controller Module | |
| NWPK - Network Packs | |
| RCT - Remote Concentrator Terminal | |
| REM - Remote Equipment Module | |
| RSLC - Remote Subscriber Line Module Controller | |
| RSLE - Remote Subscriber Line Equipment | |
| RSLM - Remote Subscriber Line Module | |
| SCM - Subscriber Carrier Module (DMS-1) | |
| SCS - SCM-10S shelf (SLC-96) | |
| SRI - Subscriber Remote Interface pack | |
| NTWK Network | |
| ACT - AC Testing definition | |
| D1PK - DS-1 interface pack (SCM-10S) | |
| DCM - Digital Carrier Module | |
| 1FAC - Interface packs | |
| LCM - Line Concentrating Module | |
| LPK - Line Concentrating Equipment line packs | |
| NWPK - Network packs | |
| PACK - Peripheral Equipment packs | |
| PMS - Peripheral Maintenance System packs | |
| PSHF - Peripheral Equipment Shelf | |
| RCT - Remote Concentrator Terminal | |
| REM - Remote Equipment Module | |
| RSHF - Remote Shelf | |
| SBLN - Standby line | |
| SCM - Subscriber Carrier Module | |
| SCS - SCM-10S Shelf (SLC-96) | |
| SLC - SLC-96 | |
| SLPK - SLC-96 Line Packs | |
| SRI - Subscriber Remote Interface (RLCM) | |
| ODQ Office Data Query | |
| ACDN - Access Directory Number | |
| CG - Carrier group | |
| CNTS - Counts | |
| DN - Directory Number | |
| DTRK - Digital Trunks (line and trunk) | |
| LINE - Lines (line and trunk) | |
| PIN - Personal Identification Number | |
| STOR - Memory Storage | |
| TG - Trunk Group | |
| TRK - Trunks (line and trunk) | |
| QTRN Query Translations | |
| ADDR - Address Translations | |
| EBSP - Enhanced Business Services prefix translations | |
| ESAP - Emergency Stand-Alone Prefix | |
| PRFX - Prefix translations | |
| SCRN - Screening translations | |
| TRVR - Translation verification | |
| ROUT Routes | |
| CONN - Nailed-up connections | |
| DEST - Destinations | |
| POS - Centralized Automatic Message Accounting positions | |
| ROUT - Routes | |
| TR - Toll regions | |
| SNET CCS7 Signaling Network | |
| SNLS - Signaling Link Set | |
| SNL - Signaling Link | |
| SNRS - Signaling Network Route Set | |
| TG Trunk Groups | |
| INC - Incoming trunk groups | |
| OUT - Outgoing trunk groups | |
| 2WAY - Two-way trunk groups | |
| THGP Thousands Groups | |
| TRAC Call Tracing | |
| TRK Trunks | |
| DTRK - Digital Trunks | |
| TRK - Analog or digital recorded announcement trunks | |
| TRNS Translations | |
| ADDR - Address translations | |
| EBSP - EBS prefix translations | |
| ESAP - Emergency Stand-Alone prefix | |
| PRFX - Prefix translations | |
| SCRN - Screening translations | |
| V. SPEC SHEET | |
| Maximum # Subscriber Lines: 10,800 | |
| (in stand-alone mode) | |
| Maximum # Trunks: 3,408 | |
| - Incoming Trunk Groups: 127 | |
| - Outgoing Trunk Groups: 127 | |
| - Two-way Trunk Groups: 127 | |
| - Maximum Routes: 512 | |
| - Maximum Trunks per Group: 255 | |
| Directory Numbers: 16,000 | |
| Office Codes: 8 | |
| Home Numbering Plan Area: 4 | |
| Thousands Groups: 64 | |
| Number of Network Groups: 1 or 2 | |
| Total Network Capacity: | |
| - One Network Module: 5,400 POTS lines + 600 trunks | |
| - Two Network Module: 10,800 POTS lines + 1,200 trunks | |
| Traffic | |
| - Busy Hour Calls 38,000 | |
| - Average Busy Season 29,000 | |
| Busy Hour Attempts | |
| - CCS per line 5.18 centi call seconds | |
| - CCS per trunk 27.0 centi call seconds | |
| - Total CCS 133,000 centi call seconds | |
| Outpulsing DP, MF, or DTMF | |
| Inpulsing | |
| - Trunks DP, MF, or DTMF | |
| - Lines DP or DTMF | |
| Register Capacity | |
| - Outgoing DP=16 digits | |
| DTMF=16 digits | |
| MF=14 digits+KP+ST | |
| LEAS MF=20 digits+KP+ST | |
| [LEAS Route Access] | |
| - Incoming DP=14 digits | |
| DTMF=16 digits | |
| MF=14 digits | |
| VI. LIMITED GLOSSARY | |
| DP - Dial Pulse. A form of signaling that transmits pulse trains to indicate | |
| digits. Slow compared to DTMF and MF. Made obsolete by DTMF. Old | |
| step-by-step switches use this method, and there are still quite a few | |
| subscriber lines that use DP, even though DTMF is available. | |
| In-band Signaling - Transmitting control signals in the 300 - 3300 hz voice | |
| band, meaning that they're audible to subscribers. | |
| Out-of-band Signaling - Transmitting control signals above or below the 300 - | |
| 3300 hz voice band. See SS7, CCS7. | |
| DTMF - Dual Tone Multi-Frequency. A form of in-band signaling that transmits | |
| two tones simultaneously to indicate a digit. One tone indicates the | |
| row and the other indicates a column. A fast, technically simple way of | |
| dialing that is in use almost all over the United States. White boxes | |
| generate DTMF tones, a.k.a. "Touch Tones" or Digitones. See DP, MF. | |
| MF - Multi-frequency. A form of in-band signaling similar to DTMF, except the | |
| signals are encoded differently (i.e., the row and column tones are | |
| different, because the keypad for MF tones isn't laid out in a rectangular | |
| matrix). These are the "operator tones." Blue boxes generate these | |
| tones. See DTMF, In-band signaling. | |
| CCS7 - Common Channel Signaling 7. Part of the Signaling System 7 | |
| specification, CCS7 transmits control signals either above or below the | |
| voice band to control switch equipment, so control signals may be | |
| transmitted simultaneously with voice. See SS7. | |
| SS7 - Signaling System 7. An inter-switch signaling protocol developed by | |
| Bellcore, the RBOCs' research consortium. Relatively new, this protocol | |
| can be run only on digital switches. See CCS7, CLASS. | |
| CLASS - Custom Local Area Signaling Services. Several subscriber-line features | |
| that are just being introduced around the United States at the time of | |
| this article. See SS7, CCS7. | |
| Centrex - A scheme that turns a switch into an off-site PBX for business users. | |
| It can usually co-exist with existing lines. | |
| If anyone has any more questions, contact me at WWIVNet THE CAVALIER@3464. | |
| Thanks to Northern Telecom (the nicest sales staff in the world of switch | |
| manufacturers, with a killer product to boot!), Pink Flamingo, Taran King, | |
| Grim, and the crew who supported the NFX in "days of yore." | |