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AT&T 7400 series, 7500 series, 7100 series, 2500 series Extended Super Frame, Robbed-Bit Signaling

Models: 7400 series 2500 series 7200 series 7500 series 7300 series 7100 series

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1-26MULTIPLEXED COMMUNICATION

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FRAME	FRAME BIT
NUMBER	DEFINITIONS

1DATA LINK F BIT (DL)

2CRC-6 F BIT

3DATA LINK SIGNAL

4FRAME SYNC PATTERN

5DATA LINK SIGNAL

6CRC-6 F BIT

7DATA LINK SIGNAL

8FRAME SYNC PATTERN

9DATA LINK SIGNAL

10CRC-6 F BIT

11DATA LINK SIGNAL

12FRAME SYNC PATTERN

13DATA LINK SIGNAL

14CRC-6 F BIT

15DATA LINK SIGNAL

16FRAME SYNC PATTERN

17DATA LINK SIGNAL

18CRC-6 F BIT

19DATA LINK SIGNAL

20FRAME SYNC PATTERN

21DATA LINK SIGNAL

22CRC-6 F BIT

23DATA LINK SIGNAL

24FRAME SYNC PATTERN

FRAME BIT
			CHANNEL 1			CHANNEL 2
			CHANNEL 1			CHANNEL 2

			8-BITS

			8-BITS

			8-BITS

	0		8-BITS

			8-BITS
						ROBBED BIT (OPTIONAL)
			7-BITS	A		ROBBED BIT (OPTIONAL)

			8-BITS

	0		8-BITS

			8-BITS

			8-BITS

			8-BITS
						ROBBED BIT (OPTIONAL)
	1		7-BITS	B		ROBBED BIT (OPTIONAL)

			8-BITS

			8-BITS

			8-BITS

	0		8-BITS

			8-BITS
						ROBBED BIT (OPTIONAL)
			7-BITS	C		ROBBED BIT (OPTIONAL)

			8-BITS

	1		8-BITS

			8-BITS

			8-BITS

			8-BITS
						ROBBED BIT (OPTIONAL)
	1		7-BITS	D		ROBBED BIT (OPTIONAL)

Figure 1-8.The Extended Super Frame

Robbed-Bit Signaling

In every 6th frame, robbed-bit signaling (RBS) replaces (that is, "robs") the least-signiﬁcant bit (LSB) of each channel. It replaces this bit with the signaling information for that channel. For D4, the 6th and 12th frames carry RBS; for ESF, the 6th, 12th, 18th, and 24th frames carry RBS (refer to ﬁgures 1-7and 1-8,respectively).

Because the signaling information is carried embedded within each channel, RBS signaling is also called inband signaling.

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AT&T 7400 series, 7500 series, 7100 series, 2500 series, 7200 series, 7300 series Extended Super Frame, Robbed-Bit Signaling

Contents

Definity Communications System Page Contents Multiplexing Outside the Switch Communication System Networking AN OverviewTandem TIE Trunk Networks Distributed Communications System DCS Data Connectivity AN OverviewSpecial Data Features Data Communications CapabilitiesData Communications Configurations Related Documents Synchronization of Digital FacilitiesGlossary Trunking Terms and Capabilities Communications ProtocolsIndex List of Figures DSU MpdmFigure B-1 Options for Synchronization Figure B-11 External and Internal Reference Levels List of Tables BCCEIA RS-449 V.24 LEADS/DEFINITIONS EIA RS-232C V.28 LEADS/DEFINITIONSEIA RS-232D V.28 LEADS/DEFINITIONS EIA RS-366 LEADS/DEFINITIONSXvi Contents Prerequisite Skills and Knowledge About this DocumentDocument Organization Part ∙ Glossary ∙ IndexHOW to Make Comments about this Document AT&TXx about this Document Introduction to Connectivity 2INTRODUCTION to Connectivity Analog Transmission Transmission TypesDigital Transmission Analog-to-Digital Conversion Analog VS. Digital 6TRANSMISSION Types Transmission States Entering the SwitchVoice Transmission 8TRANSMISSION States Digital Switch Exiting the Switch ⎜ ModuleCircuit Packs Data Transmission Protocol Layers12TRANSMISSION States Originating Switch Destination Protocols Used Layer 1 ProtocolsLayer 2 Protocols Protocol States⎜DMI Mode Code Connectivity Rules16TRANSMISSION States Frequency-Division Multiplexing Multiplexed CommunicationTypes of Multiplexing Time-Division MultiplexingStatistical Multiplexing Multiplexing Over DS1 FacilitiesAlternating Mark Inversion Line CodingZero Code Suppression ZCS Line Coding B8ZS Line Coding Signal Inversion Restricted ⎜ Unrestricted⎜ DMI 7Data-Module Capabilities Part 2 D4 Framing FramingD4 Framing SignalingESF Framing Robbed-Bit Signaling ESF 24th-Channel Signaling⎜ Channels 24th Channel ⎜ 24th Channel ⎜ Frame No⎜ DMI-BOS Trunk Types/Destinations ⎜ Signaling Types⎜ Isdn PRI Multiplexing Outside the Switch Multiplexing onto T1 TrunksCDM CEM Host Digital DMI PBX Getting the Signal Ready for the Central Ofﬁce Compressing the SignalAltering Channel Assignments on T1 Trunks DR23N DR18M DR18W DR23W Multiplexing with MicrowaveMicrowave System T1 Trunk Capacity Demultiplexing10.Possible Multiplexed Connections Statistical Multiplexing Application TrunkingLocal Exchange Trunks Tie Trunks Miscellaneous Trunks Special-Access TrunksAuxiliary Trunks Release Link Trunks RLTsAdvanced Private Line Termination Aplt Trunks Remote Access TrunksHost-Access Trunks ConnectivitySystem 85/G2 Administration Administration OptionsSignaling Types Signaling Protocols Trunk TypeGroup Type System 75/G1 AdministrationComm Type DS1 OptionsInterface Circuit Trunk TablesTrunking 44TRUNKING 11.Generic 1 and Generic 2 Digital Trunks Voice BCC 46TRUNKING Trunking 48TRUNKING Trunking 50TRUNKING Trunking 52TRUNKING Communication System Networking AN Overview Types of Networks Network Evolution DCS Software ⎜ Network Type S75/G1 S85/G2 PackagePEC Software CapabilitiesSystem 75 and Generic 1 UDP Package DIMENSION, System 85, and Generic 2 Multipremises Package System 75 and Generic 1 PNA PackageDistributed Communications System Network Call ProcessingUniform Numbering Internal Dial PlanRouting the Call DAC + EXT To ARS Auxiliary Call Information Automatic Alternate Routing Selecting a Routing Pattern∙ RNX ∙ The FRL of the call ∙ Where the trunk group appears in the list of preferencesSelecting a Trunk Group Modifying the DigitsAutomatic Route Selection Analyzing the Dialed NumberCommunication System Networking AN Overview To AAR Selecting the Routing Pattern Networking Feature Parameters Network AdministrationPrivate Network Trunks ⎜ Maap ⎜ Vmaap System Definity Feature PBX 20COMMUNICATION System Networking AN Overview Tandem TIE Trunk Networks Interactions with Other Networks2TANDEM TIE Trunk Networks Attendant Lines ⎜ Main Satellite ⎜ Trunks MS/T Configurations Main-Satellite ConﬁgurationMain-Tributary Conﬁguration MS/T Features Networking Package Multipremises with ETA Main Networking Package PNA, ETN Routing Incoming Calls Routing Outgoing CallsOther Routing Capabilities Engineering ConsiderationsInteractions Page ETN Configurations ETN Trunks Page Access and Bypass Access Tie Trunks Off-Net Trunks FeaturesUniform Numbering Plan Attendant ETN Interactions with Other Networks Extension Number Portability Clusters Software-Deﬁned Network Call Routing SDN to ETN Call Routing ETN to SDN Release Link Trunk Networks CAS and ACD Centralized Attendant Service Automatic Call DistributionDistributed Communications System Clusters Main-Satellite/Tributary NetworksDistributed Communications System DCS DCS Clusters Switch Node CapacityDCS Links Signaling Link Speed Signaling LinksSwitch Physical Links ⎜Logical Channels/Link Signaling Link ProtocolTransmission Media Direct Link DCS Connections Linkage Design Distributed Communications System DCS MTDM/MPDM DCS Signaling Link ConnectionsEquipment Distance Limitation System 75 or Generic 1 G1 to System 75 or G1System 75/G1 Signaling Channel DCP Mtdm System 85 or Generic 2 G2 to System 85 or G2Modem System 75 or Generic 1 G1 to System 85 or Generic 2 G2 RS232C to RS449 Conversion Dciu Transparent Attendant Features Dimension Signaling LinksTransparent Features Attendant Call WaitingAlphanumeric Display Attendant Control of Trunk Group Access⎜ ACA Automatic Circuit AssuranceBusy Veriﬁcation of Terminal Lines Class-of-Service/Restriction DisplayTrunk Group Busy/Warning Indicators Calling Number DisplayAlerting-Distinctive Ringing Transparent Voice Terminal FeaturesAutomatic Callback on Busy or No Answer Call Waiting Call Coverage ToneCall Forwarding Leave Word Calling LWC Without APAudio Information Exchange Audix Features Transparency Call Transfer/Conference20.AUDIX in a DCS Network Definity PBX ⎜ Feature 22DISTRIBUTED Communications System DCS Administration Considerations Distributed Communications System, Issue 3Dimension PBX Data Connectivity AN Overview Data Communications Variables Communications ProtocolsDigital PBX Public Switched Network Pooled Modem Analog vs. Digital Synchronous vs. Asynchronous∙ ∙ ∙ Simplex vs. Half-Duplex vs. Full-DuplexParallel vs. Serial Transmission SpeedCreating Switch Packet vs. Circuit Switches Type of Communications ChannelTransmission Mode Changes and Modem Pools Channel Information Bearer vs. Signaling ChannelsChannel Assignment Dial-up vs. Dedicated Connections Special Data Features Terminal DialingComputer Dialing ⎜Data Services FeaturesData Call Setup From a Voice Terminal Data Hot LineData Restriction Data ProtectionData Privacy Data Only Off-Premises ExtensionOff-Premises Data-Only Extension Conﬁgurations Data Communications Capabilities 2DATA Communications Capabilities DTE Compatibility DTE ConnectionsProtocol Converters Terminal Emulators PC/PBX or PC/ISDNData Modules DCE PossibilitiesVoice Terminal Adjunct Data Modules ADUs Data Module CharacteristicsStandalone Data Modules ModemsDTE Connections Dtdm ADM ⎜ PC/PBXPC/PBX PC/ISDNModem Pooling Connections DCP TIP-RING 12DTE Connections Data Module LAN Topology Local Area Network ConnectionsLAN Protocol LAN Transmission Media LAN ConnectorsAdvantages of a Communications System in a LAN Environment LAN LAN Access to/from LANs That Use Other Operating SystemsType Operating Gateway PC System SoftwareLocal Area Network Connections Remote PC Communication Between the LAN and Other Networks ISN CommunicationX.25 Router System Package Type Operating CommunicationsSNA Gateway Communication System as a LAN Backup 12.LAN/SNA ConnectivityPublic and Private Data Network Connections Accunet Packet ServiceAPS Access Public Data NetworksCircuit-Switched Public Data Networks SDS and Sddn ApplicationsPublic and Private Data Network Connections MPDM/M1 Public and Private Data Network Connections DTE Mpdm Terrestrial Private Data Network Links Private Data NetworksPrivate Connections Through Accunet T1.5 and T45 MPDM/M1* AMI 28PUBLIC and Private Data Network Connections ⎜AMI Satellite Private Data Network Links Isdn Gateway Telemarketing Host ConnectionsIntegrated Telemarketing Gateway 22.Telemarketing Gateway Conﬁguration For further details, see 34TELEMARKETING Host Connections Data Network Administration 36DATA Network Administration Data Communications Configurations DSC and PSC Connections DSC 4DATA Communications Configurations SNA Node Connections File Transfers Connections Through Public or Private Data NetworksVideo Teleconferencing Image Processing FAX Transmittal8DATA Communications Configurations Operation Related DocumentsGeneral Reference2RELATED Documents Related Documents Dimension AdministrationSystem 75 and Generic 6RELATED Documents Sales ServiceSystem 85 and Generic 8RELATED Documents Sales 10RELATED Documents Synchronization of Digital Facilities Need for SynchronizationFigure B-1.Options for Synchronization Synchronization Hierarchy 4SYNCHRONIZATION of Digital Facilities Synchronization of Digital Facilities ∙ DDS Figure B-3.Stratum Levels for the Synchronization Hierarchy System 85 and Generic 2 Synchronization ArchitecturePage Primary RED YEL Good LOS Misf Primary Secondary Reference Indicators ⎜ Reference⎜ Indicators ⎜ Blue REDSystem 75 and Generic 1 Synchronization Architecture Figure B-6.Tone-Clock Synchronizer Nonduplicated, Generic System 75 and Generic 1 Synchronization Software OperationCriteria for Switching to the Secondary Reference Criteria for Switching Back to the Primary ReferenceExternal Synchronization Clock CROSS-CONNECT B25A Cable Output Figure B-9.External-Clock Interface Selecting a Timing Source for the Switch Network Synchronization and EngineeringInternal Reference Selection Rules RuleExample for Rule Figure B-13.Proper Use of Backup Facilities Page Figure B-15.Optimal Diverse Routing Figure B-16.Less Than Optimal Diverse Routing Figure B-17.Excessive Cascading Figure B-19.Excessive Synchronization from One Node External-Reference Selection Rules Rules 2 ThroughMisconception Availability of Synchronization SourcesFact USE of Generic 2 AS a System Clock Reference Line-Only Mode DS1/DMI-BOS ANN11 or TN767Conclusions on Synchronization ISDN-PRI Trunk FacilitiesUSE of Generic 1 AS a System Clock Reference Line+Trunk Mode DS1/DMI-BOS ANN35 or TN767 with TN555DMI-MOS ANN35 or TN767 with TN555 Trunk-Mode ISDN-PRI TN767Trunk-Mode Interface ISDN-PRI + Robbed Bit TN767 Line-Only Mode DS1/DMI-BOS TN767Trunk-Mode DS1/DMI-MOS TN767 32SYNCHRONIZATION of Digital Facilities Trunking Terms and Capabilities Wire Tie TrunkAddress Signaling Frequently Used TermsAuto or Automatic-incoming Alerting SignalsAPLT-Advanced Private Line Termination Auto or Automatic-outgoingCustomer Provided Access Ccsa or Common Control Switching ArrangementCX Signaling or Composite Signaling Cut-Through Mode of OperationDelay-Dial Outgoing Delay-DialDelay-Dial Incoming Delay-Dial Start-Dial DdsdDial Repeating Tie Trunk Derived E&M Lead SignalingDesigned Trunks Dial-PulseLead Signaling or Ear & Mouth Signaling Direct AccessEpscs or Enhanced Private Switched Communications Service Standard or Type 1A and Type I compatible or Type 1BETN Trunking Facilities FX or Foreign ExchangeGlare Glare ResolutionGlare Detection Immediate Start Ground StartHigh-Usage Trunk Group Immediate Start IncomingIntermachine Trunk IMT Interdigit Time-outIntermediate High-Usage Trunk Group Intertandem TrunkMain PBX Out-of-Band SignalingParty Test Signal Main-Satellite TrunksSenderized Mode of Operation Reverse BatterySF or Single Frequency signaling Signal ConverterStop-Go Signaling Signaling TypeSpecial Access Connections Supervisory SignalingType of Dialing Touch-Tone SignalingTrunk Type or trunk group type Type of OutpulsingWink-Start Incoming Wats Wide Area Telephone Service TrunkWink-Start Outgoing Suggestions and Helpful Hints Trunking Characteristics Table Signaling TypesSystem 85, or Dimension PBX Switch aSupervision Signaling Tion Generic ⎜GROUP/CALL TypeSwitch B GROUP/CALL Type23/FX-DOD OUT DODIN/DID GROUP/CALL Type Signaling 27/WATS OUT 26/WATS28/WATS-DOD OUT ⎜⎜ E&M 35/TIE ESS 5ESS ⎜OTHER ⎜ LS ⎜ RB ⎜ System 85, or ⎜DIMENSION PBX ⎜ ⎜57/CAS RLT-OUTGOING From Branch ⎜66/CAS RLT-INCOMING Main Satellite⎜DIAL-TONE with Analog Data Modem Side Digital Data ⎜DATA Module Side 103/HOST AccessLine Side 104/HOST Access Trunk SideOther 32TRUNKING Terms and Capabilities Communications Protocols Data-Link Layer OSI ModelPhysical Layer Network LayerPage Figure D-1.OSI Reference Model Application Layer Session LayerPresentation Layer Standard ProtocolsTable D-1.Some Ccitt Digital Standards Table D-2.Some Ccitt Analog Standards Ccitt X.26 RS-423A FED-STDTable D-2.Some Ccitt Analog Standards Other Common Standards CCITT-ISOAT&T Protocols EIADigital Multiplexed Interface Data Mode CapabilitiesData Modes Applications DescriptionControl Data DCP DS1/DMI/BOS Channel 14COMMUNICATIONS Protocols Communications Protocols Flag Digital Communications Protocol Or multipoint BX.25 Communication Pathways and Endpoints Message, Packet, and Frame SldhLead Definitions SBA SCFSCB SBBRL/CG CH/CIRDA SDASTA RSACRQ DPRACR PNDDDA BBABBB DDB⎜ PIN 8LEAD Definitions Networking FEATURES--AVAILABILITY Matrix ⎜⎜ R1 Networking FEATURES--AVAILABILITY Matrix Contd ⎜ NA ⎜ Uniform Numbering ⎜ Plan Note 6NETWORKING FEATURES--AVAILABILITY Matrix Abbreviations CSU CRCCSM DACFAX ETAETN FEPMtdm MpdmMS/T NCPSNA SDNSMT TehoAB-6ABBREVIATIONS ADM GlossaryACU AVDADS Automatic Alternate Also high-volume tandemAudix Standalone Routing AARBit-oriented signaling Service BccosBipolar signal Message-oriented signalingCcitt BSCCPU COS CcisCOR CPESee network channel-terminating equipment See data communications equipmentDCS cluster DCS node Dciu linkDCP DCS See bit rateDDC DDDSee digital telephone DMI/MOS DCS DMI-BOSDMI-MOS DS1Communications systems and switch Error-free secondESS electronic switching Framing format Extended trunk accessBX.25 DCIU/PI Hdlc LAN Lapd Keyboard dialing Kilo bits per second kbpsSee basic rate interface See primary rate interface Also wide area network Listed directory numberLocal area network LAN Local exchange companyNcte NAUPAD PVC PDMRobbed-bit signaling 921, and signaling system numberRemote access trunk Protocol converter PCSdlc TDM UCD UNPWats Wide Area Service Wats trunkTelecommunications Service TelecommunicationsIndex ARS 2-4,2-7,2-8,2-14plan Bypass access trunk 1-37,4-7,4-8,5-1,5-4,C-2IN-2 Index Logical 6-3,D-19restricted 1-20unrestrictedChannel bank 1-9,1-10,1-29,1-30,B-20frame Dial access code 2-2,2-5,2-10,2-13,2-17,3-1,4-4CRC 1-25CSMA/CD 8-13CSU DAC 2-2,2-5,2-10,2-13,2-17,3-1,4-4,4-7,4-8,4-9,6-23DMI 1-14, D-11 Mode 1-15,1-16,1-42,2-13,9-1MOS6digitizer DS1-ContdFRL 2-10, 2-13 D4 1-24, 1-27ESF 1-24, 1-27 Gateway 7-2DCS 1-36,2-3,5-14 Statistical 1-17,1-18,1-34LOS B-9,B-13 LWC 6-18,6-21,6-24 ETN 1-36,2-2,2-8,3-1,4-1,5-1,6-1Analog 1-7,9-2trunk PAD 7-2,8-21PCM 1-5,1-7,1-14,1-18,B-1 DS1 1-13,1-16,1-18PRI 1-13, D-11 RS-232C1-13,D-9Physical layer 1-11,1-15,D-2,D-9 RS-232C1-13,6-31-39, C-3, C-5, C-6 RNX 2-10Subnet trunking 2-11, 2-14, 4-9 Intelligent main 2-4, 4-4, 4-7TCM 2-11,6-23 Analog 1-3,7-2,7-4 Bypass access 1-37,4-7,4-8,5-1,5-4T1 carrier 1-6,1-18,1-32 ﬁnal 5-2,C-9Uniform numbering 2-8, 5-1, 5-5 Uniform dial plan 2-5, 2-8, 2-9Analog 1-9 Auxiliary 1-10, 1-35IN-12 Index