___.___ _______ _______ . _____ _______ _,____ . ______ _______ ____ __ \\ | // \\---// \\ // ^ \\__/_ \\---// (_____/ ^ \\___/ \\___// (____// -+ MED +- .oO Abbreviations & Descriptions Oo. The following contains bt-related acronyms which could be used at a social-engineering level, or, if you're like us, simply interest, (or obsession??)... If the one youre looking for doesnt appear below then it may come under something else so have a browse. ---- AAR Automatic Alternative Routing. AAS Automatic Announcment Subsystem. In a local exchange it provides the recorded announcements (`Voice Guidance'). This is done by the SIS in a trunk exchange. ACE Automatic Crossconnection Equipment. ACP Access Control Pair. AEQ Automatic Announcement Equiptment. AIR Alarm Interface Controller. AJG Analogue Junctions Group. ALE Analogue Local Exchange. AMC Apparatus Maintenance Costing System. This is the repairs information subsystem. AMS Account Management System. APT Alarm Port. ARAB Alarm Reset And Busy. ARR Automatic Re-Routing. ARU Alarm Reporting Unit. ASU Advanced Services Unit - FNET (Feature Net). ASPEN Automatic Speech Exchange Network. ATD Adhoc Task Duty. ATE Automatic Telephone Exchange. AUS Access Utility Subsystem. AXS Auxiliary Supervisor. ---- BCD Binary Coded Decimal. BPS Bill Production Subsystem. (CSS). BTRL BT's Research Laboratories. Located in Martlesham Heath, near Ipswich in Sussex. ---- CAB Cable Access Box, the green things at the end of each road.. with everyones lines in. CAP Circuit Access Point. CAS Call Accounting Subsystem. Uses the caller infomation to charge the subscriber for a call and then increments the callers record table. CAS Channel Associated Switching. CC Computer Centre. CCITT International Telegraph and Telephone Consultative Committee. CCR Concentrator. CCS Call Connect System. CCS Common Channel Signalling. CCU Colocated Concentrator Unit. CCR Concentrator. CCX Concentrator Extra Parameter . CDF Charge Determination Facility. Subsystem of the TXE4. CGVPN Cyclone Global Virtual Private Network. One of the so called 'intelligent' switching networks. CIM Common Interface Module. (NJR). A bridge between TR and external systems. CMA Coordinated Management Approach. The EBP & CSP in TXE4 are together known as the CMA. CMH Call Monitoring Handler. Subsystem of the TXE4. CNI Calling Number Interception. COMFORTE COMputers FOR Telephone Exchanges. COW Clerk Of Work. CPE Customer Premises Equipment. CPI Cable Pair Identification. CPI Calling Path Indicator. CPS Call Processing Subsystem. It has overall control over any call. It registers the state of lines (busy/free etc..), Stores class of Service (out going barred, incoming barred etc..), controls the star facilities, controls timeouts and communicates with other software such as CAS. CSDB Cashless Services DataBase. This is a four processor non-stop intelligent database. CSMA Carrier Sense Multiple Access. CSO Centralized Service Observation. CSO Computer Service and Operations. CSO Contract Supervising Officer. CSP Central Site Processor.(TXE). CSPU Cashless Services Processing Unit. Processes chargecard calls. CSS Customer Service Systems. CTF Current Task File. CUG Closed User Group. ---- DACS Digital Access Carrier System. A pair gain device which allows two pstn channels over a single pair of wires. DAM Alarm Monitor. DAS Directory Assistance System. DASS Digital Access Signalling System. DCCE Digital Cell Centre Exchange. This is an exchange that provides service to its own customers and acts as parent for RCUs and analogue exchanges, in which case it fowards traffic to the nearest DMSU. It also switches tandem traffic between DLSU's. DCD Data Compiler/Decompiler. DCD LOOP The process of Decompiling data and feeding the output in as the input to the compiler. DCE Data Circuit terminating Equipment. DDC District Data Center. DDI Direct Dialling In. DDT Digital Line Termination. DDSN Digitally Derived Services Network. (0800, 0345 etc...) DDSC Digital Derived Service Centre. Switch type controlling DDSN. DESS Digital Exchange Support System. DIO Direct Input Output. This is the System X 'bus'. It allows intercommunication between hardware and software resources. DISC Digital International Switching Centre. DJSU Digital Junction Switching Unit. This is a switching unit in a high telephone density local network which performs a tandem switching function, but has no customer connections. DLSU Digital Local Switching Unit. General term for DLPE. It provides service to its own customers also provides other facilities dependent on it's role as either a DCCE or DLE. DLE Digital Local Exchange. This is a DLSU which may host RCUs for DCCEs and also act as a parent for ALEs which will be replaced by RSUs parented by the DLE or DCCE. DLM Data Load for Manpower. (MERIT). DLPE Digital Local Processor Exchange. DLT Digital Line Termination DMS100 Digital Multiplexer Switch, make by AT&T Bell, and used in England as an International Gateway Exchange. DMSU Digital Main Switching Unit. Provides a fully interconencted trunk network. Each DMSU catchment area will compromise of several old GSC areas. The DMSU will switch traffic both between and within catchment areas. DMU Dialled Meter Unit. DN Directory Number DPC Destination Point Code. DPCM Differential PCM. DPLE Digital Principle Local Exchange. Main exchange for an area. DPT D Switch Port. (System X). DS3 Digital Subscribers Switching Subsystem. It is used to connect subscribers to the local exchange. It is connected via PCM links. DSG District Support Group. (BT District Staff). DSS Digital Switch Subsystem. The DSS carries out all the switching functions on a System X exchange - Trunk or local. DSSS Digital Subscribers Switching Subsystem. See DS3. DSW D-Switch. (System X). DTE Data Terminating Equipment. DUP Data User Port. DWI Display Work Instructions - A commonly found trash. ---- EBP Exchange Based Processor. ECTE Exchange Computer Terminal Equiptment. EIN Employee Identification Number. EL Exchange Log. EN Equipment Number. END Exchange name documentation. EPT E Switch Port. (System X). ERS Emergency Repair Service. ESS Electronic Switching System. ESW E Switch. (System X). ETA Enhanced Test Access. EWL Exchange Work List. ---- FAIS Field Access Interface System. Used in conjunction with WMS. FAW Frame Alignment Word. FDX Frequency Detector Auxiliary. (System X). FGX Frequency Generator Auxiliary. (System X). FNET FeatureNet. FMR FaultMan's Ringback. Dial the FMR (3 digit starting with 1 - generally 17x) number and replace handset, upon ringback the service should provide a quick analysis of any problems. FP Functional Processor. FRB Same as FMR. ---- GEC GP Global Profile. GPT GEC/Plessey Telecommunications. GPX General Purpose Auxiliary. (System X). GSC Group Switching Centre. ---- HHT Hand Held Terminal. HQCPC HQ Central Product Codes System. Provides product related info to TR via CIM. Used for validation purposes (ie COW codes). HTD Hardware trial period. HWX Howler Auxiliary. (System X). ---- I/C Incoming IDA Integrated Digital Access. IDDF Intermediate Digital Distribution Frame. IGE International Gateway Exchange. INDB Intelligent Network Database. INS Integrated Network System. IRC Inter-Relay Chat. (heh). IS In Service. ISDN Intergrated Services Digital Network. iSDX ISIS Inland Services Infomation System. ISIS is basically a book and manual service. Within ISIS it is possible to find infomation through indexing. ISOS In Service Operational Support. (Manufacturer Staff). The ISOS would be called in when an urgent problem needs a higher level of support, or if a major service failure occurs they can be called in quicker than the PSG. ITU International Telecommunications Union. Previously CCITT. ---- JAX Junction Circuit Auxiliary. JERA Joint Electronic Research Agreement. This was struck up between the P.O, Ericsson, GEC, STC, ATE and Siemens Edison Swan in 1956, they then manufactured several experimental exchanges which gave way the the electronic TXE range. JGX Junction General Purpose Auxiliary. JR MIS Job Related Management Information System. JSW Junction Q Switch. JUN Junction Subscriber. ---- KNL 'Kin 'Ell ---- LAN Local Area Network. LAP Local Access Point. LAP Link Access Protocol. LCG Line Controller Group. LCN Line Controller Number. LID LAN Interface Device. LLAR Local Line Automatic Routine. LLE Large Local Exchange. LNE Subscriber Line. LNO London Network Operations. LPI Line Pair Indicator. LPT Local Control Point Port. LTS Line Test System. LSSU Link Status Signal Unit. LUN Line Unit. ---- MAC Measurement and Analysis Centre. MAIU Meter Alarm & Interface Unit. MCO Maintenance Clearance Officer. OMU worker responsible for making sure all tasks and routines have been carried out. MCS Maintenance Control Subsystem. Carries out maintenance functions. MCU Main Control Unit. MDF Main Distribution Frame. MED Possibly the best H^P group in the world. :) MEER Miscellaneous Electronic Equiptment Rack. MERIT Management of Employee Information for Telecom. Supplies employee information to other BT systems. MF4 Multi Frequency signaling System No 4. MFX MF4 Test Auxiliary Board. MIS Management Information System. MLE Medium Local Exchange. MMI Man-Machine Interface. MMIS Man-Machine Interface Subsystem. The MMIS allows engineers to control and manage the exchange through VDT's etc.. MML Man-Machine Language. MOJ Metering Over Junction. MOOS Manually Out Of Service. MOP Maintenance Officer Program. MP ManPower resources subsystem. (NJR). Maintains personnel records to allow the hierarchical framework to function. MPCS Multi Party Connection Subsystem. The MPCS allows 3 to 10 subscribers to be connected together at the same time. MPR Microprocessor. MRA Malfunction Reporting Alarm. MSC Main Switching Centre. MSN Multiple Subscriber Number. MSC Main Switching Centre. MSS Management Statistic Subsystem. Keeps records of the junction routes in the local exchange and keeps traffic records for DS3s and RCUs under it's control and also for the AAS. MTS Message Transmission Subsystem. Terminal part of CCS link. It transmits and receives messages sent between distant CPSs and carries out error checks on messages and re-transmits if necessary. MUX Multiplexer. ---- NAC Number Area Code. NAC Network Administration Centre. NACC Network Administration Computer Centre. NAS Nation Account System. Provides local reference data and extracts info from TR via CIM. (CSS). NCI Network Control Interface. Just one CSS logon mechanism. NFU Network Field Unit. NIC Network Interlock Code. NIN National Insurance Number. Used by bt for security to identify employees when logging on to a system etc. NJR National Job Recording system. (CSS). NNI Network Nodal Identity. Every exchange has one. NMS Network Management Subsystem. (CSS). NOMS1 Network Operations and Maintenance System. NOU Network Operations Unit. NSS Network Synchronisaton Facility. NT Network Termination. ---- O&M Operations & Maintenance. Guidance folders on many topics. O/G Outgoing. OCB Outgoing Calls Barred. OCHC OHS Order Handling Subsystem. (CSS). OLO Other Liscenced Operators. OMC Operations & Maintenance Centre. Collects data from exchanges and monitors data for presentation for the OMC staff (Traffic, Sales, Operation & Maintenance Unit. (OMU) ) OMU Operation and Maintenance Unit. Room where engineers monitor the performance of the exchanges, and receive data collected by the OMC. There is one or more connected to each OMC. OMU staff can send data to the OMC to control the exchanges connected to it. OOS Out Of Service. OPC Originating Point Code. (MTS). OSC Operations Support Centre. OSD Operations Surveillance Duty. OSI Open Systems Interconnection. OSSU OUC Organisational Unit Code. --- PABX Private Automatic Branch Exchange . PACE Plessey Automatic Commisioning Equiptment. PAD Packet Assembler / Disassembler. PARIS Pay and Related Information System. The payroll issuing system. PATE4 Print Analysis - TXE4. PBX Private Branch Exchange. PCM Process Control Module. (TNS). PCM Pulse Code Modulation. PCP Pair Concentration Point. Green boxes again, as CAB. PCS Subscriber's Private Circuit. PDN Public Data Network. PFT Pass Fail Thresholds. PLA Per Line Auxiliary. PLEXUS/SDF Computer centre with both PLEXUS and ICL systems. PMSL POE Path Of Entry. PRAT Primary Rate Access Terminal. PRISM The personnel records computer which supplies data to NJR. It was replaced by MERIT in early 94. PSG Product Support Group (BT Headquarters Staff). PSGs can be called in if there is a problem on site. They give the authority for any emergency design modifications carried out without authority having being gained in advance. PSN Packet Switched Network. PSO Public Service Operator. PSS Packet Switch Service. PSS Packet Switching Stream. PSTN Public Switched Telephone Network. PSU Power Supply Unit. PTO Public Telephone Network Operator. PUS Processor Utility Subsystem. See DIO. PUS2 The Central Processor which provideds the processing power and storage facilites for all other subsystems. PXSM Pre-Extension Site meeting. ---- QSU Q-Switch ---- RAD Resistance Adjustment. RALP Remote Alarm Lamp Panel. Part of early warning (fire) system. RATES Remote Access Test Equiptment System. RCC Remote Concentrator Centre. Point with many RCU's. RCU Remote Concentrator Units. These concentrate the lines and are considered to be part of the DLSU to which they are connected. The RCU is situated away from the Telecom building in a more convienient place and it is the apparatus that divides the lines and gives them their equipment numbers. REMT Remote. RFA Ringer Fuse Alarm. RHD Repair Handling Duty. RHS Request Handling Subsystem. RLTF Remote Line Test Facility. RMCC Remote Multi-Concentrator Unit. Two or more subscribers connected in a RCC. ROU Remote Observation Unit. R2PU Release 2 Processor Utility. The System X central processor. RSHS Repair Service Handling Subsystem. (CSS). RST Routing, Switching and Transmission plan. This brought about the modernization of the UK telephone network in 1960. It demanded a network structure somewhat similar to that which we have today. RTU Remote Terminal Unit. ---- SAC Service Address Code. SADIE Subscriber Automatic DIsconnect Equitment. (TXE). Used to place a subscribers line TOS (Temporalily Out Of Service). SALT Subscribers Automatic Line Testing. For System X and Y exchanges. The code for this is generally 175 and has the same job as the FaultsMans Ringback but is more advanced with increased options after the ringback. SBR ENS Exchange Subscriber. SCH Set-up Call Handler. Subsystem of the TXE4. SDP System data page. SMF System Manager Facility. Administration subsystem of the TXE4. SPM Subscriber's Private Meter. SPM Subscriber Pulse Metering. SPU Speech Interworking Unit. SIN Site Identification Number. SIS Signalling and Interworking Subsystem. Used as an interface between a System-X exchange and analogue exchanges. It converts analogue to 30 channel PCM for connection to the DSS. SIU Slide-In-Unit. These are the individual hardware components of the TXD. SLAP Subscriber Line Access Point. SLCU Small Line Concentrator Unit. SLU Subscriber Line Unit. SMF System Management Facility. STX Substitution Auxiliary. ---- TAC Test Access Console. TAD Task Allocation Duty. TAPS Telecomms Apparatus Provision costing System. An installation information system used by BT. TBN Transmission Bearer Network. TCC Through Connected Circuit. TCC Transit Call Control. TCR Task Completion Report. TCR Terminating Circuit Record. TE Telephone Exchange. TE Terminating Equipment. THF Task History File. THW DSSS Test Highway. TIBS Telephone Input Billing System. TID Terminal Identity. T&JR Trunk and Junction Routiner. TKO TrunK Offering. TN Trunk Network. TNC Test Network Controller. TNCP Test Network Control Process. T-NET BT's big network in the sky. Allows connections to all of BT's other network systems. Terminal access is via satellite. Tnet Telenet. TNET Tymnet. TNO Test Network Operations. TNS Test Network Subsystem. The TNS controls the accessing of and testing of all digital and analogue junctions and subscriber lines. It uses SIS to access analogue junction lines, DSS to access digital junctions and DS3 tto access subscribers lines. TOC Type Of Circuit Digits. TOS Temporalily Out of Service. TPN Telephony Process Number. TPOE Translation Point Of Entry. TR Time Recording subsystem. (NJR). Allows imput of time and allowance data. Deals with temporary loans of staff. Holds payroll data reference tables. TRAPP TRAPP circuits are used so that calls to a particular code are only given access to part of a route. TRS Transmission Repeater Station. TSB Time Switch Bus. TSC Transit Switching Centre. TSVC Telephone Service and Vechicle Centre. TTT Transmission Test Threashold. TUG Technical User Guide. TXD #'s A method of labelling types of exchange by number that forms part of the exchange's Network Nodal Identity which appears all on documents specific to the particular exchange. TXE Telephone eXchange Electronic.. most commonly in the form of a TXE4, or TXE4A (cost reduced). TXK Telephone Exchange Crossbar. (electronic). TXS Telephone Exchange Strowger. (electronic). ---- UID User Identity UM Unit Manager. The UM is responsible for the service given by the TXD exchanges in his OMC area and the organisation of staff. UXC Utilities Card UXD5 Unit eXchange Digital v5. Digital Exchange developed from the CDSS1 (Monarch) PABX and used mostly in rural Scotland. ---- VAN Value Added Network. VMB Voice MailBox. VRS Voice Response System. Allows remote testing of subscriber's line given code and number. There are possibly other systems under the heading VRS because it's not exactly very use specific. ---- WMS Work Manager System. Used by BT engineers to download their infomation for jobs of the day. Generally used via a portable field terminal and accoustic coupler. It is accessable from any termination point in England. WN Worldwide Networks. WNI Worldwide Networks Intstruction. ---- X.25 DTE-DCE interface for packet mode terminals (hosts) to packet switched networks. (PDN access). XD ExDirectory. ----