ISDN ACRONYMS

TELECOM ACRONYMS

1TR6 (Ger) FTZ regulation (close to CCITT Q.930/931)

2B1Q 2 binary data, 1 quarternary redundance

3PTY Three Party Service (I.254 B)

4B3T 4 binary data, 3 ternary redundance (MMS43)

5B6B 5 binary data, 6 binary redundance (code for OFT lines) a/b two wire phone connection (T&R)

ABM Asynchronous Balanced Mode ( -> SABME)
ABME ABM extended
ACA Asynchronous Communication Adapter
ACD Automatic Call Distribution
ACFA Advanced CMOS Frame Aligner PEB2030
ACI Answer Controller Interface (IOM2 Monitor Command)
ACIA Asynchronous Communications Interface Adapter
ACK Acknowledge
ACM Address Complete Msg. (SS7: in ISUP)
ACSE Association Control Service Element
ACU Automatic Calling Unit
ADC American Digital Cellular
ADC Analog to Digital Converter
ADCCP Advanced Data Communication Controll Procedure
ADMA Advanced DMA Controller SAB82258 ADPCM Adaptive PCM
AERM Alignment Error Rate Monitor AFE Analog Front End
AFI Authority and Format Identifier (ISO 7498)
AGND Analog Ground AI Activate Indication (C/I channel code)
AI Artificial Intelligence AIS Alarm Indication Signal
AIU AI Upstream ALE Adress Latch Enable
AM Amplitude Modulation
AMC Add-on Module Connector (-> SIPB)
AMI Alternate Mark Inversion Code
ANM Answer Msg. (SS7: in ISUP)
ANS Answer Msg.
ANSI American National Standards Institute
AOC Advice of Charge (I.256 B)
AP Application (OSI Layer 7)
APD Avalanche Photo Diode
API Application Interface
APPC Advanced Program to Program Communication (IBM)
AR Activation Request (C/I channel code)
ARCOFI Audio Ringing Codec Filter PSB2160
ARCOFI-SP ARCOFI + speakerphone function PSB2165
ARCOS ARCOFI Coefficient Support Program
ARCOTI SIPB Telephone Module
ARD AR Downstream
ARL Activation Request Local loop (C/I channel code)
ARM Activation Request Maintenance (C/I channel code)
ARM Asynchronous Response Mode
ARN Activation Request
ARQ Automatic Repeat Request
ARU Activation Request Upstream
ASCC2 Advanced Serial Communication Controller SAB825??
ASCII American Ntl. Standard Code for Information Interchange
ASE Application Service Element
ASIC Application Specific Integrated Circuit
ASM Analog Subscriber Module
ASP ARCOFI Signal Processor
AT&T American Telephone & Telegraph
ATD Async. TDM
ATI Awake TI
ATM Analog Trunk Module
ATM Asynchronous Transfer Mode
AU Access Unit
AUP Access Unit Port
AW (Ger) termination resistor
AWI Awake Indication

B8ZS Bipolar with 8 Zeros Substitution (T1 PRI)
BA Basic Access BAKT (Ger) Basic Access Concentrator
BAMX (Ger) Basic Access
MUX BAS Basic Activity Subset (T.62, BAS of OSI session layer) BBD0/1 Binary 0s or 1s detected in B and D channels BCC Block Check Character BCCP Bearer CCP BDS Basic Data Service BEL Bell BER Bit Error Rate BHC Busy Hour Call BIB Backward Indicator Bit (SS7) BICU Bus Interface Control Unit BIFIFO Bidirectional FIFO BIR Bit Receiver BIR Bus Interface Register
BISDN Broadband ISDN
BISYNC Binary Synchronous Communications
BIT Bit Transmitter
BITR Bit Transceiver
BLA Blocking Acknowledgement (SS7: in ISUP)
BLO Blocking (SS7: in ISUP) BMU Basic Measurement Unit (DIP)
BOC Bell Operating Companies
BORSCHT Battery, Overvoltage, Ringing, Supervision, Coding, Hybrid, Testing
BOP Byte Oriented Protocol
BOS Bit Oriented Signaling
BPSK Binary PSK
BR Bit Robbing (CAS-BR)
BRG Baud Rate Generator
BS Backspace
BSI British Standards Institution
BSN Backward Sequence Number (SS7) BT British Telecom
BVS Basic Voice Service C/I Command/Indicate

CA Collision Avoidance (->CSMA/)
CAM Communication Access Method
CAM Computer Aided Manufacturing
CAM Content Adressable Memory
CAM Control Administration Module
CAN Cancel CANC Cancel (I.451)
CAS Cannel Associated Signaling
CBA Change Back Acknowledgement (SS7: in MTP)
CBD Change Back Declaration (SS7: in MTP)
CBEMA Computer and Business Equipment Manufacturers' Assc.
CC Common Channel (CAS-CC)
CC Connection Confirm
CC Country Code (ISO 7498)
CC1 Call Control 1 (IOS)
CCA Computer Content Architecture (ISO 8637/2)
CCBS Completion of Call to Busy Subscribers (I.253 C)
CCIR Consultative Committee for Radiocomunication (International Radio Consultative Committee)
CCIS #7 Common Channel Interoffice Signaling (Japan, SS #7 Subset)
CCITT Consultative Committee for Internat. Telephone and Telegraph
CCNC CCS Network Control
CCP Call Control Part
CCR Clock Configuration Register
CCR Continuity Check Request (SS7: in ISUP)
CCRC Corrupt
CRC (IOM2 Monitor Command)
CCS Common Channel Signaling
CCU Communication Control Unit
CD Call Deflection (I.252 E)
CD Collision Detection (->CSMA/)
CDI Connected Line Identification (I.251 C/E)
CDMA Code Division MA
CDR Collision Detect input line
CE Conducted Emission (EME)
CE Collision Elimination (->CSMA/)
CEI Comparable Efficient Interconnection
CEN European Committee of Standards
CENELEC European Committee of Standards (Electrotechnics)
CEP Connection Endpoint
CEPT European Conference of Post/Telecom Administrations
CFI Configurable Interface (SIPB)
CFNR Call Forwarding No Reply (I.252 C)
CFP Call Forwarding Busy (I.252 B)
CFU Call Forwarding Unconditional (I.252 D)
CGB Circuit Group Blocking (SS7: in ISUP)
CGBA CGB Acknowledgement
CGM Computer Graphics Metafile (ISO DIS 8632)
CGU Circuit Group Unblocking (SS7: in ISUP)
CGUA CGU Acknowledgement
CIF Common Intermediate Format (for ISDN high end video)
CIC Circuit Identification Code
CID Connection Identification
CIP Control Interface Port
CIP Control Interface Port
CIRR C/I Receive Register
CIXR C/I Transmit Register
CK Checkbits CKS Clock select bit
CLIP Calling Line Identification Presentation (I.251 C)
CLIR Calling Line Identification Restriction (I.251 D)
CLK Clock
CLS Connectless-Mode Service
CLT Communications Line Terminal
CM Connection Memory
CMC Call Modification Completed (SS7: in ISUP)
CMR Call Modification Request (SS7: in ISUP)
CMRJ CMR reject (SS7: in ISUP)
CN Connection
CO Central Office
COA Change Over Acknowledgement (SS7: in MTP)
COO Change Over Order (SS7: in MTP)
CODEC Coder/Decoder
COLP Connected Line Identification Presentation (I.251 E)
COLR Connected Line Identification Restriction (I.251 F)
COM/EXP PCM-Compander/Expander
CONF Conference Calling (I.254 A)
CONN Connect Msg. (I.451)
COP Call Offering Procedure
CORC Commands and Responses Definition and Compressing Program (IOS) CorNet Corporate Network Protocol (ECMA and CCITT Q.930/931 oriented) D-channel layer 3 protocol for private IPABX
COS Connection-Mode Service
COT Central Office Terminal (opposite to RT)
COT Continuity (SS7: in ISUP)
CPD Common Packet Data Channels
CPE Customer Premises Equipment
CPG Call Progress (SS7: in ISUP)
CPU Central Processing Unit SAB80188-2 SAB80C166 SAB80C5xx
CQM Circuit Group Query (SS7: in ISUP)
CQR CQM Response
CR Carriage Return
CR Control Response
CRC Cyclic Redundancy Check
CRCOK CRC ok! (C/I channel code)
CRED Credit Card Calling (I.256 A)
CREF Connection Refused
CS Cable Switching
CS Conducted Susceptibility (EMS)
CSMA/ Carrier Sense Multiple Access
CSO Cold Start Only (in EOC)
CSDN Circuit-Switched Data Network (T.70)
CSPDN Circuit-Switched Public Data Network
CSR Clock Shift Register
CST Call State or Current State or Change State (quasi SDL)
CT Call Transfer (I.252 A)
CTMC Communications Terminal Module Controller
CTS Clear to Send
CUG Closed User Group (I.255 A)
CW Call Waiting (I.253 A)

D-CTL D Channel Controller (IDEC)
DAC Digital to Analog Converter
DACOM Data Communictions Corp. of Korea (ROK)
DACK DMA ACK DAEDR Delimitation, Alignment and Error Detection Procedure in Receive Direction
DAML Digital Added Main Line (pair gain)
DAP Document Application Profile
DASS2 Digital Access Signaling System 2 (BT, DPNSS subset)
DBCS Data Bank Control System
DBOS Data Bank Organization System
DBSS Data Bank Security System
DBP (Ger) German Federal Post
DC Device Cinfirmation (C/I channel code)
DCn Device Control n
DCC Data Country Code (ISO 7498)
DCE Data Circuit-terminating Equipment
DCE Data Communications Equipment
DCH D-Channel Handling bit
DCL Data Clock (i.e. IOM2)
DCME Digital Circuit Multiplexing Equipment
DCS Data Communications Subsystem
DD Data Downstream (i.e. IOM2)
DDI Direct Dialing-In (I.251 A)
DDN Defense Data Network
DDS Dataphone Digital Service
DDX Digital Data Exchange
DEAC Deactivation (C/I channel code)
DECT Digital European Cellular Phone
DEE (Ger) data terminal DEL Delete
DET Detatch Msg. (I.451)
DI Deactivation Indication (C/I channel code)
DIA Document Interchange Architecture
DIC Digital Concentrator
DID DI Downstream
DID Direct Inward Dialing
DIF Digital Interface
DIGON (Ger) digital local network (Berlin)
DIP Document Interchange Protocol (lower sublayer of OSI layer 6)
DIR Direction
DIS Disconnect
DISC Disconnect (LAP-D Command, I.451)
DISD Direct Inward Subscriber Access
DIU Deactivate Indication
DIU Digital Interface Unit
DIV (Ger) digital exchange
DIVF (Ger) DIV for long distance service
DIVO (Ger) DIV for local service
DL5MDA someone who collects each ISDN abbrevation crossing his way
DLAB Divisor Latch Access Bit
DLC Data Link Control
DLCI Data Link Connection Identifier (I.440: SAPI+TEI)
DLE Data Link Escape (ASCII Control)
DLE Delete
DLS Digital Line Section
DLUC Digital Line Unit Control
DM Disconnected Mode (LAP-D Response)
DMA Direct Memory Access
DNHR Dynamic Nonhierarchical Routing
DNIC Data Network Identification Code (ISO 7498)
DOD (USA) Dept. of Defense
DPC Destination Point Code (SS7)
DPCM Differential PCM
DPLL Digital Phase Locked Loop
DPNSS Digital Private Network Signaling System (BT)
DPSK Differential Phase Shift Keying
DR Deactivate Request (C/I channel code)
DRAM Dynamic RAM
DRCS Dynamically Redefinable Character Sets
DR Deactivation Request
DRE Direction
DSC Digital Subscriber Controller Am79C30A
DSGLA (Ger) DLS DSI Digital Speech Interpolation
DSM Digital Switching Module
DSMX (Ger) digital signal multiplexer
DSP Digital Signal Processing
DSP Domain Specific Part (ISO 7498)
DSR Data Set Ready
DSU Data Servicing Unit
DT Data Through (C/I channel code in test mode)
DT1 Data Form Class 1
DTAM Document Transfer Access and Manipulation
DTC Digital Telephone Controller (ARCOFI + IBC + ICC)
DTE Data Terminal Equipment
DTM Digital Trunk Module
DTMF Dual Tone Multi Frequency (Dial) PSB8593
DTR Data Terminal Ready
DU Data Upstream (i.e. IOM2)
DU Deactivation Request Upstream (C/I channel code)
DUP Data User Part DVA (Ger) data processing equipment
DYRECT SIDES Dynamic Real Time Communication Tester (in SITEST, tests IOS on Board)

EA Expedited Data Acknowledgement (SS7: in SCCP)
EA Extended Adress
EBCDIC Extended Binary Coded Decimal Interchange Code
EC Echo Canceller EC European Community
ECL Emitter Coupled Logic
ECMA European Computer Manufactueres Association
EDI Electronic Data Interchange
EEPROM Electrically Erasable Programmable Read Only Memory
EIn Error Indication n (C/I channel code)
EM Encription Module
EM End of Medium (ASCII Control)
EMC Electromagnetic Compatibility
EME Electromagnetic Emission
EMI Electromagnetic Interference
EMS Electromagnetic Susceptibility
EMV EMC (German) ENQ Enquiry
EO End Office
EOC Embedded Operation Channel
EOM End of Message
EP Expedited Data (SS7: in SCCP)
EPIC Extended PIC PEB2055
EQ Equalizer
ERC Error Control (IOS)
ESC Enhanced Speech Circuit PSB4505/6
ESC Escape (ASCII Control)
ESCC2 Extended high level Serial Communication Controller SAB82532 (2 channel multi protocol controller)
ESCC8 like ESCC2, but 8 channels SAB82538
ESF Extended Super Frame
EST established
ET Exchange Termination
ETB End of Transmission Block
ETRI Electronics and Telecommunications Research Institute (ROK)
ETX End of Text
EVST (Ger) end exchange
EWSD (Ger) electronic dialing system (Digital)

FA Frame Aligner

FAA Facility Accepted (SS7: in ISUP)

FAC Facility

FACD Facility Changed Msg.

FAR Facility Request (SS7: in ISUP)

FAS Frame Alignment Signal FAX Faximile FC Feature Control FC Frame Control FCC Federal Communications Comission (USA) FCS Frame Check Sequence FDDI Fiber Distributed Data Interface (X3T9.5) FDM Frequency Division Multiplex FDMA FDM Access FEBE Far End Block Error (IOM2 Monitor Message) FEC Forward Error Correction FECC Front End Communication Computer FF Form Feed FIB Forward Indication Bit (SS7) FIFO First In First Out (storage) FIN Facility Information Msg. FISU Fill In Signal Unit (SS7) FJ Frame Jump (C/I channel code) FM Frequency Modulation FMM Finite Message Machine FNBE Far and Near end Block Error (IOM2 Monitor Message) FOT Forward Transfer (SS7: in ISUP) FP Functional Protocol FPC Frequency Comparison Pilots FPS Fast Packet Switching FRAC Frame Aligner Circuit PEB2030 FRJ Facility Rejected Msg. (SS7: in ISUP) FRMR Frame Reject (LAP-D Response) FRQ Facility Request Message FS File Separator FSC Frame Synchronization Clock (i.e. IOM2) FSN Forward Sequence Number FTP File Transfer Protocol (DOD) FTZ (Ger) Central Telecom Technical Office (of DBP)

GAP (EC) Group of Analysis and Provision (for ONP)
GB Great Britain
GC Group Card
GCI General Circuit Interface (IOM/U(k0)-Interface)
GCR General Configuration Register Ger German
GP Group Processor
GPPC General Purpose Power Controller PSB2121
GPS Global Positioning System
GRA GRS Acknowledgement
GRS Circuit Group Reset (SS7: in ISUP)
GS Group Separator
GTEI Global TEI
GWY Gateway

H Hold state (in EOC)
H- High-
HAC Hands-Free Add-On Circuit (for speakerphone) PSB45030
HDB3 High-Density Bipolar 3 (CEPT PRI)
HDLC High Level DLC
HDTV High Definition TV
HFR Hardwara Failure Rate
HI High Impedance (C/I channel code)
HI Highway Interrupt
HL IT Siemens Semiconductors (HL), Info Technics (IT)
HOLD Call Hold (I.253 B)
HSCC High Level Serial Communication Controller SAB82520
HSCX extended
HSCC SAB82525 HT Horizontal Tabulator
HTI Highway Transfer Interrupt
HU High-Usage trunk
HW PCM Highway

I Information (LAP-D Command) I- Information (numbered I-Frames) I/O Input/Output IAM Initial Address Msg. (SS7: in ISUP) IBC ISDN Burst Transceiver Circuit PEB2095 IBFN (Ger) integrated high bandwith long distance network IC Incoming Call (X.25) ICOM (Taiwan) Integrated Communication ICAO International Civil Aviation Organization ICC ISDN Communications Controller PEB2070 IDA (GB) Interated Digital Access (B64+B8+D8) IDEC ISDN D-channel Exchange Controller PEB2075 IDI Initial Domain Identifier (ISO 7498)

IDN (Ger) integrated data network IDPC Integrated Data Protocol Controller SAB79C401

IEC International Electrotechnical Comission IEC ISDN Echo Cancellation Circuit

IEC-T IEC for 4B3T PEB2090 IEC-Q1 IEC for 2B1Q PEB2091 IEC-Q2 IEC-Q specially for LT and NT1 (without microprocessor) PEB2092 IEC-Q3 IEC-Q with parallel processor interface (i.e. for DAML) PEB2093 IEC-P (old name of IEC-Q3) IEPC ISDN Exchange Power Controller PEB2025 IFRB International Frecuency Registration Board IFS (Switzerland) integrated telecom service IGS Idenitfy Graphic Subrepertoire (Teletex) IKZ (Ger) pulse dial

ILC ISDN Link Controller

IM Input MUX IMC

IOS Mailbox Control

IMMU IOS Memory Management Unit

IMP Interpersonal Messaging Protocol (X.420: P2)

INF Information (SS7: in ISUP) INR Information Request (SS7: in ISUP)

INS (Japan) Information Network System (B64+B16+D8)

INT Interrupt (i.e. C/I channel code)

IOC Integrated Optical Circuit

IOM ISDN-Oriented Modular (Architecture and Interfaces)

IOM2 extended IOM IOS ISDN Operational Software SIPB6013

IP Intermediate Point

IP Internet Protocol (TCP/IP, DOD) IPABX ISDN PABX IPAC ISDN PC Adapter Circuit PEB21?? IPAT ISDN Primary Access Transceiver PEB2235 IPB SIPB IPBC IOM2 PBC (old name for EPIC) IPC Interprocess Communication IPCS IOS Process Control System IPP IOS Protocol Part IRPC ISDN Remote Power Control PSB2120 ISAC-P ISDN Subscriber Access Controller (S Bus, PABX, U) PEB20950 ISAC-S ISDN Subscriber Access Controller (S Interface ICC+SBC) PEB2085 ISDN Integrated Services Digital Network ISM ISDN Switching Module ISO International Organization for Standardization ISP Intermediate Service Part ISPC International Signaling Point Code (SS7)

ISPBX Integrated Systems PBX ISSS ISDN Supporting System ISTA Interrupt Status Register ISUP ISDN User Part (SS7: Q.76X) IT Inactivity Test (SS7: in SCCP) ITAC ISDN Terminal Adaptor Circuit PEB2110 ITSTC Information Technology Steering Committee (CEN, CENELEC, CEPT) ITU International Telecommunication Union IVD Integrated Voice Data IWF Interworking Facility (Gateway)

IWU Interworking Unit (Gateway)

JDC Japan Digital Cellular

KTA Korea Telecommunication Authority (ROK)
KVST (Ger) node exchange
KZU (Ger) signaling converter

L3-ERC Layer 3 Error Control (IOS)

L3M Layer 3 Mgr. (IOS)

LAN Local Area Network

LAPB (LAP-B) Link Access Procedure of Balanced Mode

LAPD (LAP-D) Link Access Procedure of D-Channels

LAPM (LAP-M) Link Access Protocol for Modems

LAPX LAPB extended (T.71, for half duplex teleservice)

LATA Local Access and Transport Areas

LBBD Loopback B1, B2 and D channel request (Command in IOM2 Monitor and EOC)

LBn Loopback channel Bn request (Command in IOM2 Monitor and EOC)

LC Line Card

LCN Logical Channel Number

LCS7 Link Controller for Signaling System No.7 PEB3040 (layer 2, CCITT Q.703, upgraded HSCX, pin compatible)

LE Local Exchange (contains D-CTL)

LF Line Feed

LH Line Hunting (I.252 F)

LI Length Indicator (SS7)

LIU Line Interface Unit

LL Logical Link

LLC Low Level Controller SIPx6100

LLD Low Level Device Drivers (IOS)

LLID LL Identifier

LLL Last Look Logic

LLP Link Layer Protocol (LAPD)

LNA Low Noise Amplifier

LOF Loss of Frame LRC Longitudinal Redundancy Check LRN Local Reference Number

LSEC Loss of SEC (C/I channel code) LSL Loss of Signal Level (C/I channel code)

LSSU Link State Signal Unit (SS7) LSU Loss of Signal level of U interface (C/I channel code)

LSUE LSU Error condition (C/I channel code) LT Line Termination LT-S LT on S bus LT-T LT on T interface

LTD LT Disable (C/I channel code) LTG Line Trunk Group LTU Line Trunk Unit LTUC LTU Control LU 6.2 protocol for APPC LWL (Ger) OFT

MA Multiple Access (Primary) MAP Manufacturing Automation Protocol

MAP Mobile Application Part

MCI Malicious Call Identification (I.251 G)

MDF Main Distribution Frame

MF Mainboard Firmware (IOS)

MF Multi Frame

MFJ Modification of Final Judgement

MFC Multiple Frame operation Control (IOS)

MH Modified Huffman code (FAX)

MHS Message Handling Service

MIP Microprocessor Interface Port

MIPS Million Instructions per Second MML Man Machine Language MMS43 Modified Monitoring State 43 Code (4B3T) MMU Memory Management Unit (IOS) MNP Microcom Networking Protocol

MOC Ministery of Communication MOD Ministery of Defense MON Monitor Channel (i.e. IOM2) MP Microprocessor MPC MP Command MPDU Message Protocpl Data Units (X.411) MR Modified READ (Relative element address designate, FAX) MR Monitor Read (flow control bit in IOM2)

MS Menue Software (SIPB.EXE) Msg Message MSN Multiple Subscriber Number (I.251 B)

MSU Msg. Signal Unit (SS7) MTA Message Transfer Agent (X.400) MTAE Message Transfer Agent Entity (X.400)

MTP Message Transfer Part (SS7: Q.701-Q.710) MTP Message Transfer Protocol (X.411: P1) MTS Memory Time Swich PEB2040 MTSC MTS CMOS (512 incoming channels) PEB2045 MTSL MTS Large (1024 incoming channels) PEB2047 MTSS MTS Small (256 incoming channels) PEB2046 MUNICH Multichannel (32) Network Interface Controller SAB20320

MUSAC Multipoint Switching and Conferencing Unit PEB2245

MUX Multiplexer MW (Ger) service word

MX Monitor Transmit (flow control bit in IOM2)

N(R) (NR) Receive Sequence Number N(S) (NS) Transmit Sequence Number

NAK Negative Acknowledge NB Narrow Band NCC Notify Corrupted CRC (in EOC) NCU Network Control Unit NCP Network Control Point (in a SDN) NCTE Network Channel Terminating Equipment (FCC: NT1) NDC National Destination Code (i.e. area code) NDU Network Data Unit

NEBE Near End Block Error (IOM2 Monitor Message) NET (EC) European standards of telecommunication NF (Ger) low frequency NFS Network File System NFT Network File Transfer NLP Network Layer Protocol NORM return to Normal (IOM2 Monitor Command/Message) NRM Normal Response Mode (HSCX) NRZ Non Return to Zero NRZC NRZ Change NRZI NRZ Inverted NRZM NRZ Mark NSP Network Service Part (SS7: SCCP+MTP) NStA (Ger) PBX NT Network Termination NT1 NT serving Layer 1 (NCTE, network interface of NT, between reference points T and U) NT2 NT serving Layer 1 to 3 (subscriber interface of NT, between reference points S and T) NT/S NT Simulator SIPB7020 NTM NT Test Mode (IOM2 Monitor Message) NUC Nailed-up Connection NUA (international) Network User Address NUI Network User Identification NUL Null NUP National User Part NVM Non Volatile Memory (EEPROM)

NWI Network Interface

OA&M Operations, Administration & Maintenance (SS7: Q.79X)

OC Office Communication OCP Origination Point Code (SS7) ODA Office Document Architecture

OEIC Optoelectronic Integrated Circiut OFT Optical Fiber Tube OM Output MUX OMAP Operations and Maintanance Application Part OMC Operating and Maintainance center ONA Open Network Architecture (FCC: Computer Inquiry III) ONP Open Network Provision OPC Originating Point Code

OPDU Operations Protocol Data Unit (X.411: P3)

OSI Open Systems Interconnection

OVST (Ger) local exchange

OWG Optical Wave Guide P/F Poll/Final Bit

PABX Private Automatic Branch Exchange PAD Packet Assembly/Disassembly Device PAM Pass Along Method (SS7: in ISUP) PAM Primary Access Method PAS Protocol Architecture Specification for IOS (PCT)

PBC Peripheral Board Controller PEB2050/51 PBX Private Branch Exchange PC Power Controller PC Primary Center

PCL PCM data Clock PCM Pulse Code Modulation

PCN Personal Communication Network (UK, mobile comm.) PCR Preventive Cyclic Retransmission (SS7: in MTP)

PCSN Public Circuit Switched Network (?) PCT IOS Program Coding Tools (SDL oriented) SIPO6021 PDC Primary Digital Carrier

PDM Power Down Mode

PDU Protocol Data Unit (X.400)

PDN Public Data Network

PFOFF Power Feed OFF (C/I channel code)

PFS Page Format Selection (Teletex) PFS PCM Frame Synchronisation Signal PH Packet Handler PH- Physical- PIC PCM Interface Controller PEB2052 PIOCS Physical I/O System PIP

PCM Interface Port PIU PCM Interface Unit PKT Packet PLC Physical Link Control (IOS) PLD Partial Line Down (Teletex) PLIC PCM Line Interface PLL Phase Locked Loop PLU Partial Line Up (Teletex) PM Phase Modulation PN Pseudo Noise (Code) PNP Private Numbering Plan (I.255 B) PPU Power Providing Unit PRI Primary Rate Interface PS Packet Switching PSDN Packed-Switched Data Network (T.70) PSF Packet Switching Facility

PSK Phase Shift Keying PSL IOS Protocol Source Library

PSPDN Packed-Switched Public Data Network PSR Phase Shift Register PST SIDES Protocol Software Development

PSTN Public Switched Telephone Network (T.70) PU Power Up (C/I channel code) PUM PU Mode PVC Permanent Virtual Circuit

Q-CIF Quarter CIF (for ISDN low end video)
QSC Quad S Interface Circuit PEB2084
QTAM Queued Telecom Access Method

RA Rate Adaption
RAD Receive Adress
RAM Random Access Memory
RBEF Read Block Error counter for Far end (IOM2 Monitor Command)
RBEN Read Block Error counter for Near end (IOM2 Monitor Command)
RBOC Regional BOC
RC Regional Center
RCC Request Corrupted CRC (in EOC)
RCL Route Clock
RCI Read Controller Interface (IOM2 Monitor Command)
RCP Remote Copy
RCRE Receive Corrected Reference Equivalent
RCU Repeater Control Unit (i.e. ASIC between two IEC-Q2s)
RDS Running Digital Sum
RDY Resynchonisation indication after loss of framing (C/I channel code)
RE Radiated Emission (EME)
REC Receiver
REJ Reject (LAP-D Command/Response, I.451)
REL Release (I.451)
RES Reset (C/I channel code)
RES Resume (I.451) RES1 Reset receiver (C/I channel code)
REMSH Remote Shell
REV Reverse Charging (I.256 C)
RFI Radio Frequency Interference RID Read Identification (IOM2 Monitor Command)
RKW (Ger PCM30) FAS
RL Return Loss
RLC Release Complete Msg. (SS7: in SCCP)
RLOGIN Remote Login
RLSD Released Msg. (SS7: in SCCP)
RNR Receive Not Ready (LAP-D Command/Response)
ROK Republic of Korea
ROSE Remote Operation Service Element (TCAP subset)
RP Repeater
RPFC Read Power Feed Current value (IOM2 Monitor Command)
RPOA Recognized Private Operating Agency
RR Receive Ready (LAP-D Command/Response)
RS Radiated Susceptibiltiy (EMS)
RS Record Separator (ASCII Control)
RS Reset
RSC Reset Confirm (SS7: in SCCP and ISUP)
RSY Resynchronizing (C/I channel code)
RSYD RSY Downstream
RSYU RSY Upstream
RT Remote Terminal (opposite to COT)
RTB Retransmission Buffer
RTCA Radio Technical Commission of Aeronautics
RTN Return to Normal (in EOC)
RTS Request to Send
RTSE Reliable Transfer Service Element
RxSD Receive Serial Data
RZ Return to Zero (-> NRZ)

S- Supervisory (S-Frames)

SAA System Applications Architecture (for PS/2)

SABME Set Asynchronous Balanced Mode (ABM) Extended (LAP-D Command)

SAC Service Access Connector (-> SIPB) SAI S Activity Indicator (in EOC)

SAM Subsequent Address Msg. (SS7: in ISUP)

SANE Signaling Area/Network Code (SS7)

SAP Service Access Point

SAPI Service Access Point Identifier

SAW Surface Acoustic Wafe (Filter) B5534

SBC S Bus Interface Circuit PEB2080

SBCX SBC extended PEB2081

SBUC S Bus Connector

SC Sectional Center

SCCP Signaling CCP (SS7: Q.71X)

SCL Station Clock

SCLK Slave CLK

SCM Scramble Coder Multiplexer

SCP Service Control Point

SCR Signaling Configuration Register

SCRC Send Corrected Reference Equivalent

SD Slip Detected

SDE Submission/Delivery Entity (X.400)

SDL Specification and Description Language

SDLC Synchronous DLC

SDM Space Division Multiplex

SDN Software Defined Network

SDP Submission and Delivery Protocol (X.411)

SDT Software Development Tools SEC Signal level behind the Echo Canceller (C/I channel code)

SEL digital Selector (in TMS)

SF Service Field

SF Status Field (SS7)

SFB Set next FEBE to zero SFD Superframe Detected (C/I channel code) SGC Switching Group Control

SGH Select Graphic Rendition (Teletex) SHI Select Horizontal Spacing (Teletex) SI Sequenced Information SI Service Indicator SI Shift In (ASCII Control) SICOFI Signal Processing Codec Filter PEB2060 SICOFI2 2 channel

SICOFI PEB2260 SIDES Siemens ISDN Software Development and Evaluation System SIF Signaling Information Field (SS7) SIG Signaling equipment (in a trunk) SIGS Signaling Strobe SIN Status Indication Normal Alignment SIO Service Information Octet (SS7) SIP Serial Interface Port SIPB Siemens ISDN PC User Board SIPB 5XXX SIPB Modules SIPB 7XXX SIPB Configurations SIPMOS Siemens P MOS BUZ... BSS... BSP... SIPO 6XXX Siemens ISDN PC Software Object Code SIPS 6XXX Siemens ISDN PC Software Source Code

SITAC Siemens Isolated Thyristor AC SITEST Siemens ISDN Protocol Software Test Tools SIPO6022 SIU Subscriber Line Interface Unit SL Subscriber Line SLA Subscriber Line Adress SLC Signaling Link Code (SS7) SLD Subscriber Line Data (Bus) SLIC Subscriber Line Interface Circuit SLM Subscriber Line Module SLMA SLM Analog SLMD SLM Digital SLS Signaling Link Selection (SS7) SM Service Module SM Speech Memory SMD Surface Mounted Device SMF Sub Multi Frame SMS Service Management System SMTP Simple Mail Transfer Protocol

SNA System Network Architecture (IBM) SO Shift Out SOH Start of Header SP (Ger) storage SP Signal Point (Switching Office in SS7) SP Stimulus Protocol SPC Signaling Poiny Code (SS7) SPC Stored Program Controlled

SPCR Serial Port Control Register

SQD Signal Quality Detector

SRAM Static RAM

SS7 Signaling System #7 (CCITT)

SSC Standard Speech Circuit PSB4500/-1

SSF Sub Service Field

SSI Serial Signal Interface

SSN Subsystem Number

SSP Send Single Pulses (C/I channel code for test mode) SSP Service Switching Point ST Self Test request NT (IOM2 Monitor Message) ST Subscriber Terminal STP Self Test Pass (IOM2 Monitor Message) STATMUX Statistical Multiplexer STCR Syncron Transfer Control Register STEP SIDES Static Test of IOS and MF on board (in SITEST) STM Synchronous Transfer Mode STORY Screening Tool for Report Files (IOS) STP Signal Transfer Point (SS7) STS Space-Time-Space switch (TMS-TSI-TMS) STS Steered Tenant Service STS 2060 SICOFI software STU 2000 stand alone ISDN user board STU 2040 stand alone MTS user board STU 2050 stand alone PBC user board STU 2060 stand alone SICOF user board STUDIALO PC Software for STU 2XXX STX Start of Test SU Signaling Unit SUB Sub-addressing (I.251) SUB Substitute Character (Teletex) SUERM SU Error Rate Monitor SUS Suspend (SS7: in ISUP) SUSP Suspend (I.451) SVC Switched Virtual Circuit SVM Service Module SVP Surge Voltage Protector various SVS Select Vertical Spacing (Teletex) SWFC Sliding-Window Flow Control SYN Synchronous Idle

SYP Synchronisation Pulse

T double wire pair

T- Transportfunction- T&R two wire phone connection TA Terminal Adaption TAC TEI Assignment Control (IOS) TAC Technical Assistance Center TAP Teletex Access Protocol (X.430: P5) TC Toll Center TC Transaction Capabilities TCAP Transaction Capabilities Application Part TCM Time Compression Multiplexing (also "ping pong" or "burst" transmission, used in IBC) TCP Transport Control Protocol (DOD, IP) TCU Timing Control Unit TDC Telex Destination Code (ISO 7498) TDM Time Division Multiplex TDMA TDM Access

TE Terminal Equipment

TE Transit Exchange (contains PSF)

TEI Terminal Endpoint Identifier

TELEKOM (Ger) telecom division of DBP

TELEX Teleprinter Exchange

TELNET virtual terminal protocol

TF (Ger) carrier frequency

THL Trans Hybrid Loss

TI Test Indication

TIC Telecom IC (IOM-Bus)

TIM Timing

TKO (Ger) telecom regulations

TM Testmode

TM Trasfer Modus

TM1 Terminal 1 (IOS)

TMA Trunk Module Analog TMD Trunk Module Digital TMS Time-Multiplexed Switching TMX Trunk Module with X-interface TN Tone (C/I channel code: wake up signal) TNC Terminal Node Controller TOP Technical Office Protocol TOPQ Top of Queue (quasi SDL)

TRI Tone Ringer PSB652x TS Time Slot TSA Time Slot Assignment TSC Tristate Control TSI Time-Slot Interchange

TST Time-Space-Time switch (TSI-TMS-TSI) TUP Telephone User Part (SS7: Q.72X) TWX Teletype Writer Exchange TxSD Transmit Serial Data

U single wire pair

U- Unnumbered (U-Frames) U(k0) (Ger) U0 echo cancellation Interface U(p0) (Ger) U0 burst mode Interface UA Unnumbered ACK (LAP-D Response) UA User Agent (X.400)

UAE User Application Entity or User Agent Entity (X.400) UAI U Activation Indication (C/I channel code) UBA Unblocking Acknowledgement UBL Unblocling (SS7: in ISUP) UDLC Universal DLC UDT Unidata (SS7: in SCCP) UDTS Unidata Servive (SS7: in SCCP) UDP User Datagram Protocol UI Unnumbered Information (LAP-D Command) UIC U-Interface Unit ULCU User Level Control/Command Unit UOA U Interface Only Activation (in EOC) UP User Part US Unit Separator USART Universal Synchrounous/Asynchrounous Receiver/Transmitter USR User-to-User Information (SS7: in ISUP) UTC Unable to Comply Ack (in EOC) UTC Unacknowledged (Unnumbered) Information Transfer Control (IOS) UTM Universal Transaction Monitor UUCP Unix-System to Unix-System Copy

UUS User-to-User Signaling (I.257 A)

V(R) Receive Sequence Counter
V(S) Transmit Sequence Counter
VAC Vacuumschmelze (produces cores and transformers)
VANS Value Added Network Service
VAP Value Added Process
VAP Videotext Access Point
VC Virtual Call
VCB Virtual Circuit Bearer
VFAC Verified and Forced Account Codes
VFN Vendor Feature Node
VHDL Very High Scale IC Description Language (DOD)
VL (Ger) connecting cable
VPT Virtual Private Network
VSAT Very Small Aperture Terminal (for satellite communication)
VSP (Ger) full frame storage
VSt (Ger) exchange unit
VT Vertical Tabulator
VT Virtual Terminal
VTAM Virtual Telecom Access Method

WADS Wide Area Data Service
WATS Wide Area Telephone Service
WCI Write Controller Interface (IOM2 Monitor Command)
WDFHP recursive high pass filter + decimation filter
WDFLP recursive low pass filter + decimation filter
WDM Wavelength Division Multiplex

XAD Transmit Adress
XFIFO Transmit FIFO
XID Exchange Identification (LAP-D Command/Response)
XOFF Transmission Off (DC1)
XON Transmission On (DC3)
XPL Cross Reference Protocol Listing (PCT)

ZCS Zero Code Suppression
ZSP (Ger) intermediate (buffer) storage
ZWR (Ger) intermediate regenerator
ZZF (Ger) central office for approvals in telecommunications (DBP)
ZZK (Ger) central signaling channel