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AT&T 7300 series, 7500 series, 7100 series, 2500 series, 7200 series Data Connectivity AN Overview

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

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7. DATA CONNECTIVITY — AN OVERVIEW

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This part of the AT&T Network and Data Connectivity document explains how to use your communications system to connect one data communications device or network to another device or network. This chapter, in particular, deﬁnes some basic data communications principles, and it explains the data features that your communications system offers.

Refer to chapter 1, Introduction to Connectivity, for information on the types of transmission that can be used to carry data, and the types of trunks and multiplexing available.

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AT&T 7300 series, 7500 series, 7100 series, 2500 series, 7200 series, 7400 series manual Data Connectivity AN Overview

Contents

Definity Communications System Page Contents Communication System Networking AN Overview Multiplexing Outside the SwitchTandem TIE Trunk Networks Data Connectivity AN Overview Distributed Communications System DCSData Communications Capabilities Special Data FeaturesRelated Documents Synchronization of Digital Facilities Data Communications ConfigurationsIndex Trunking Terms and Capabilities Communications ProtocolsGlossary List of Figures Mpdm DSUFigure B-1 Options for Synchronization Figure B-11 External and Internal Reference Levels BCC List of TablesEIA RS-366 LEADS/DEFINITIONS EIA RS-232C V.28 LEADS/DEFINITIONSEIA RS-232D V.28 LEADS/DEFINITIONS EIA RS-449 V.24 LEADS/DEFINITIONSXvi Contents Document Organization About this DocumentPrerequisite Skills and Knowledge ∙ Glossary ∙ Index PartAT&T HOW to Make Comments about this DocumentXx about this Document Introduction to Connectivity 2INTRODUCTION to Connectivity Digital Transmission Transmission TypesAnalog Transmission Analog-to-Digital Conversion Analog VS. Digital 6TRANSMISSION Types Voice Transmission Entering the SwitchTransmission States 8TRANSMISSION States Digital Switch ⎜ Module Exiting the SwitchCircuit Packs Protocol Layers Data Transmission12TRANSMISSION States Originating Switch Destination Layer 1 Protocols Protocols UsedProtocol States Layer 2 ProtocolsConnectivity Rules ⎜DMI Mode Code16TRANSMISSION States Time-Division Multiplexing Multiplexed CommunicationTypes of Multiplexing Frequency-Division MultiplexingMultiplexing Over DS1 Facilities Statistical MultiplexingZero Code Suppression ZCS Line Coding Line CodingAlternating Mark Inversion B8ZS Line Coding Restricted ⎜ Unrestricted Signal Inversion⎜ DMI 7Data-Module Capabilities Part 2 Framing D4 FramingESF Framing SignalingD4 Framing Robbed-Bit Signaling ⎜ Frame No 24th-Channel Signaling⎜ Channels 24th Channel ⎜ 24th Channel ESF⎜ Isdn PRI Trunk Types/Destinations ⎜ Signaling Types⎜ DMI-BOS Multiplexing onto T1 Trunks Multiplexing Outside the SwitchCDM CEM Host Digital DMI PBX Altering Channel Assignments on T1 Trunks Compressing the SignalGetting the Signal Ready for the Central Ofﬁce Demultiplexing Multiplexing with MicrowaveMicrowave System T1 Trunk Capacity DR23N DR18M DR18W DR23W10.Possible Multiplexed Connections Statistical Multiplexing Local Exchange Trunks TrunkingApplication Tie Trunks Release Link Trunks RLTs Special-Access TrunksAuxiliary Trunks Miscellaneous TrunksConnectivity Remote Access TrunksHost-Access Trunks Advanced Private Line Termination Aplt TrunksSignaling Types Administration OptionsSystem 85/G2 Administration Trunk Type Signaling ProtocolsDS1 Options System 75/G1 AdministrationComm Type Group TypeTrunk Tables Interface CircuitTrunking 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 Software Capabilities Software ⎜ Network Type S75/G1 S85/G2 PackagePEC DCSSystem 75 and Generic 1 UDP Package System 75 and Generic 1 PNA Package DIMENSION, System 85, and Generic 2 Multipremises PackageNetwork Call Processing Distributed Communications SystemRouting the Call Internal Dial PlanUniform Numbering DAC + EXT To ARS Auxiliary Call Information Selecting a Routing Pattern Automatic Alternate Routing∙ RNX Modifying the Digits ∙ Where the trunk group appears in the list of preferencesSelecting a Trunk Group ∙ The FRL of the callAnalyzing the Dialed Number Automatic Route SelectionCommunication System Networking AN Overview To AAR Selecting the Routing Pattern Private Network Trunks Network AdministrationNetworking Feature Parameters ⎜ Maap ⎜ Vmaap System Definity Feature PBX 20COMMUNICATION System Networking AN Overview Interactions with Other Networks Tandem TIE Trunk Networks2TANDEM TIE Trunk Networks Attendant Lines ⎜ Main Satellite ⎜ Trunks Main-Satellite Conﬁguration MS/T ConfigurationsMain-Tributary Conﬁguration MS/T Features Networking Package Multipremises with ETA Main Networking Package PNA, ETN Routing Outgoing Calls Routing Incoming CallsEngineering Considerations Other Routing CapabilitiesInteractions Page ETN Configurations ETN Trunks Page Access and Bypass Access Tie Trunks Uniform Numbering Plan FeaturesOff-Net Trunks 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 Automatic Call Distribution Centralized Attendant ServiceMain-Satellite/Tributary Networks Distributed Communications System ClustersDistributed Communications System DCS DCS Links Switch Node CapacityDCS Clusters Signaling Link Protocol Signaling LinksSwitch Physical Links ⎜Logical Channels/Link Signaling Link SpeedTransmission Media Direct Link DCS Connections Linkage Design Distributed Communications System DCS System 75 or Generic 1 G1 to System 75 or G1 DCS Signaling Link ConnectionsEquipment Distance Limitation MTDM/MPDMSystem 75/G1 Signaling Channel DCP System 85 or Generic 2 G2 to System 85 or G2 MtdmModem System 75 or Generic 1 G1 to System 85 or Generic 2 G2 RS232C to RS449 Conversion Dciu Attendant Call Waiting Dimension Signaling LinksTransparent Features Transparent Attendant FeaturesAutomatic Circuit Assurance Attendant Control of Trunk Group Access⎜ ACA Alphanumeric DisplayCalling Number Display Class-of-Service/Restriction DisplayTrunk Group Busy/Warning Indicators Busy Veriﬁcation of Terminal LinesAutomatic Callback on Busy or No Answer Transparent Voice Terminal FeaturesAlerting-Distinctive Ringing Leave Word Calling LWC Without AP Call Coverage ToneCall Forwarding Call WaitingCall Transfer/Conference Audio Information Exchange Audix Features Transparency20.AUDIX in a DCS Network Definity PBX ⎜ Feature 22DISTRIBUTED Communications System DCS Distributed Communications System, Issue 3 Administration ConsiderationsDimension PBX Data Connectivity AN Overview Communications Protocols Data Communications VariablesDigital PBX Public Switched Network Pooled Modem Synchronous vs. Asynchronous Analog vs. DigitalSimplex vs. Half-Duplex vs. Full-Duplex ∙ ∙ ∙Transmission Speed Parallel vs. SerialType of Communications Channel Creating Switch Packet vs. Circuit SwitchesChannel Assignment Dial-up vs. Dedicated Connections Channel Information Bearer vs. Signaling ChannelsTransmission Mode Changes and Modem Pools Terminal Dialing Special Data FeaturesData Hot Line ⎜Data Services FeaturesData Call Setup From a Voice Terminal Computer DialingData Only Off-Premises Extension Data ProtectionData Privacy Data RestrictionOff-Premises Data-Only Extension Conﬁgurations Data Communications Capabilities 2DATA Communications Capabilities Protocol Converters DTE ConnectionsDTE Compatibility PC/PBX or PC/ISDN Terminal EmulatorsVoice Terminal Adjunct Data Modules DCE PossibilitiesData Modules Modems Data Module CharacteristicsStandalone Data Modules ADUsDTE Connections Dtdm PC/ISDN ⎜ PC/PBXPC/PBX ADMModem Pooling Connections DCP TIP-RING 12DTE Connections Data Module LAN Protocol Local Area Network ConnectionsLAN Topology Advantages of a Communications System in a LAN Environment LAN ConnectorsLAN Transmission Media LAN System Software Access to/from LANs That Use Other Operating SystemsType Operating Gateway PC LANLocal Area Network Connections Remote PC X.25 Router ISN CommunicationCommunication Between the LAN and Other Networks SNA Gateway Type Operating CommunicationsSystem Package 12.LAN/SNA Connectivity Communication System as a LAN BackupPublic Data Networks Accunet Packet ServiceAPS Access Public and Private Data Network ConnectionsSDS and Sddn Applications Circuit-Switched Public Data NetworksPublic and Private Data Network Connections MPDM/M1 Public and Private Data Network Connections DTE Mpdm Private Connections Through Accunet T1.5 and T45 Private Data NetworksTerrestrial Private Data Network Links MPDM/M1* AMI 28PUBLIC and Private Data Network Connections ⎜AMI Satellite Private Data Network Links Integrated Telemarketing Gateway Telemarketing Host ConnectionsIsdn 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 Video Teleconferencing Connections Through Public or Private Data NetworksFile Transfers FAX Transmittal Image Processing8DATA Communications Configurations Reference Related DocumentsGeneral Operation2RELATED Documents Related Documents Administration DimensionSystem 75 and Generic 6RELATED Documents System 85 and Generic ServiceSales 8RELATED Documents Sales 10RELATED Documents Need for Synchronization Synchronization of Digital FacilitiesFigure B-1.Options for Synchronization Synchronization Hierarchy 4SYNCHRONIZATION of Digital Facilities Synchronization of Digital Facilities ∙ DDS System 85 and Generic 2 Synchronization Architecture Figure B-3.Stratum Levels for the Synchronization HierarchyPage Primary ⎜ Blue RED Primary Secondary Reference Indicators ⎜ Reference⎜ Indicators RED YEL Good LOS MisfSystem 75 and Generic 1 Synchronization Architecture System 75 and Generic 1 Synchronization Software Operation Figure B-6.Tone-Clock Synchronizer Nonduplicated, GenericCriteria for Switching Back to the Primary Reference Criteria for Switching to the Secondary ReferenceExternal Synchronization Clock CROSS-CONNECT B25A Cable Output Figure B-9.External-Clock Interface Network Synchronization and Engineering Selecting a Timing Source for the SwitchRule Internal Reference Selection RulesExample 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 Rules 2 Through External-Reference Selection RulesFact Availability of Synchronization SourcesMisconception ISDN-PRI Trunk Facilities Line-Only Mode DS1/DMI-BOS ANN11 or TN767Conclusions on Synchronization USE of Generic 2 AS a System Clock ReferenceTrunk-Mode ISDN-PRI TN767 Line+Trunk Mode DS1/DMI-BOS ANN35 or TN767 with TN555DMI-MOS ANN35 or TN767 with TN555 USE of Generic 1 AS a System Clock ReferenceTrunk-Mode DS1/DMI-MOS TN767 Line-Only Mode DS1/DMI-BOS TN767Trunk-Mode Interface ISDN-PRI + Robbed Bit TN767 32SYNCHRONIZATION of Digital Facilities Frequently Used Terms Wire Tie TrunkAddress Signaling Trunking Terms and CapabilitiesAuto or Automatic-outgoing Alerting SignalsAPLT-Advanced Private Line Termination Auto or Automatic-incomingCut-Through Mode of Operation Ccsa or Common Control Switching ArrangementCX Signaling or Composite Signaling Customer Provided AccessDelay-Dial Start-Dial Ddsd Delay-DialDelay-Dial Incoming Delay-Dial OutgoingDial-Pulse Derived E&M Lead SignalingDesigned Trunks Dial Repeating Tie TrunkStandard or Type 1A and Type I compatible or Type 1B Direct AccessEpscs or Enhanced Private Switched Communications Service Lead Signaling or Ear & Mouth SignalingFX or Foreign Exchange ETN Trunking FacilitiesGlare Detection Glare ResolutionGlare Immediate Start Incoming Ground StartHigh-Usage Trunk Group Immediate StartIntertandem Trunk Interdigit Time-outIntermediate High-Usage Trunk Group Intermachine Trunk IMTMain-Satellite Trunks Out-of-Band SignalingParty Test Signal Main PBXSignal Converter Reverse BatterySF or Single Frequency signaling Senderized Mode of OperationSupervisory Signaling Signaling TypeSpecial Access Connections Stop-Go SignalingType of Outpulsing Touch-Tone SignalingTrunk Type or trunk group type Type of DialingWink-Start Outgoing Wats Wide Area Telephone Service TrunkWink-Start Incoming Suggestions and Helpful Hints Signaling Types Trunking Characteristics Table⎜GROUP/CALL Type Switch aSupervision Signaling Tion Generic System 85, or Dimension PBXGROUP/CALL Type Switch BIN/DID DOD23/FX-DOD OUT GROUP/CALL Type Signaling 28/WATS-DOD OUT 26/WATS27/WATS OUT ⎜⎜ E&M 35/TIE ESS 5ESS ⎜OTHER ⎜ LS ⎜ RB ⎜ System 85, or ⎜DIMENSION PBX ⎜ Main Satellite ⎜57/CAS RLT-OUTGOING From Branch ⎜66/CAS RLT-INCOMING⎜DIAL-TONE with Trunk Side Digital Data ⎜DATA Module Side 103/HOST AccessLine Side 104/HOST Access Analog Data Modem SideOther 32TRUNKING Terms and Capabilities Communications Protocols Network Layer OSI ModelPhysical Layer Data-Link LayerPage Figure D-1.OSI Reference Model Standard Protocols Session LayerPresentation Layer Application LayerTable D-1.Some Ccitt Digital Standards Ccitt X.26 RS-423A FED-STD Table D-2.Some Ccitt Analog StandardsTable D-2.Some Ccitt Analog Standards CCITT-ISO Other Common StandardsEIA AT&T ProtocolsData Modes Data Mode CapabilitiesDigital Multiplexed Interface Description ApplicationsControl Data DCP DS1/DMI/BOS Channel 14COMMUNICATIONS Protocols Communications Protocols Flag Digital Communications Protocol Or multipoint BX.25 Communication Pathways and Endpoints Sldh Message, Packet, and FrameLead Definitions SBB SCFSCB SBACH/CI RL/CGRSA SDASTA RDAPND DPRACR CRQDDB BBABBB DDA⎜ PIN 8LEAD Definitions Networking FEATURES--AVAILABILITY Matrix ⎜⎜ R1 Networking FEATURES--AVAILABILITY Matrix Contd ⎜ NA ⎜ Uniform Numbering ⎜ Plan Note 6NETWORKING FEATURES--AVAILABILITY Matrix Abbreviations DAC CRCCSM CSUFEP ETAETN FAXNCP MpdmMS/T MtdmTeho SDNSMT SNAAB-6ABBREVIATIONS AVD GlossaryACU ADMADS Routing AAR Also high-volume tandemAudix Standalone Automatic AlternateMessage-oriented signaling Service BccosBipolar signal Bit-oriented signalingCPU BSCCcitt CPE CcisCOR COSSee data communications equipment See network channel-terminating equipmentSee bit rate Dciu linkDCP DCS DCS cluster DCS nodeDDD DDCSee digital telephone DS1 DCS DMI-BOSDMI-MOS DMI/MOSFraming format Extended trunk access Error-free secondESS electronic switching Communications systems and switchBX.25 DCIU/PI Hdlc See basic rate interface See primary rate interface Keyboard dialing Kilo bits per second kbpsLAN Lapd Local exchange company Listed directory numberLocal area network LAN Also wide area networkNAU NctePAD PDM PVCProtocol converter PC 921, and signaling system numberRemote access trunk Robbed-bit signalingSdlc TDM UNP UCDTelecommunications Service Wats trunkTelecommunications Service Wats Wide AreaIndex Logical 6-3,D-19restricted 1-20unrestricted Bypass access trunk 1-37,4-7,4-8,5-1,5-4,C-2IN-2 Index ARS 2-4,2-7,2-8,2-14planDAC 2-2,2-5,2-10,2-13,2-17,3-1,4-4,4-7,4-8,4-9,6-23 Dial access code 2-2,2-5,2-10,2-13,2-17,3-1,4-4CRC 1-25CSMA/CD 8-13CSU Channel bank 1-9,1-10,1-29,1-30,B-20frameDS1-Contd Mode 1-15,1-16,1-42,2-13,9-1MOS6digitizer DMI 1-14, D-11Gateway 7-2 D4 1-24, 1-27ESF 1-24, 1-27 FRL 2-10, 2-13ETN 1-36,2-2,2-8,3-1,4-1,5-1,6-1 Statistical 1-17,1-18,1-34LOS B-9,B-13 LWC 6-18,6-21,6-24 DCS 1-36,2-3,5-14DS1 1-13,1-16,1-18 PAD 7-2,8-21PCM 1-5,1-7,1-14,1-18,B-1 Analog 1-7,9-2trunkRS-232C1-13,6-3 RS-232C1-13,D-9Physical layer 1-11,1-15,D-2,D-9 PRI 1-13, D-11Intelligent main 2-4, 4-4, 4-7 RNX 2-10Subnet trunking 2-11, 2-14, 4-9 1-39, C-3, C-5, C-6ﬁnal 5-2,C-9 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 TCM 2-11,6-23Auxiliary 1-10, 1-35 Uniform dial plan 2-5, 2-8, 2-9Analog 1-9 Uniform numbering 2-8, 5-1, 5-5IN-12 Index