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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 Switch Tandem TIE Trunk Networks Data Connectivity AN Overview Distributed Communications System DCS Data Communications Capabilities Special Data Features Related Documents Synchronization of Digital Facilities Data Communications Configurations Index Trunking Terms and Capabilities Communications ProtocolsGlossary List of Figures Mpdm DSU Figure B-1 Options for Synchronization Figure B-11 External and Internal Reference Levels BCC List of Tables EIA RS-366 LEADS/DEFINITIONS EIA RS-232C V.28 LEADS/DEFINITIONSEIA RS-232D V.28 LEADS/DEFINITIONS EIA RS-449 V.24 LEADS/DEFINITIONS Xvi Contents Document Organization About this DocumentPrerequisite Skills and Knowledge ∙ Glossary ∙ Index Part AT&T HOW to Make Comments about this Document Xx 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 Switch Circuit Packs Protocol Layers Data Transmission 12TRANSMISSION States Originating Switch Destination Layer 1 Protocols Protocols Used Protocol States Layer 2 Protocols Connectivity Rules ⎜DMI Mode Code 16TRANSMISSION States Time-Division Multiplexing Multiplexed CommunicationTypes of Multiplexing Frequency-Division Multiplexing Multiplexing Over DS1 Facilities Statistical Multiplexing Zero Code Suppression ZCS Line Coding Line CodingAlternating Mark Inversion B8ZS Line Coding Restricted ⎜ Unrestricted Signal Inversion ⎜ DMI 7Data-Module Capabilities Part 2 Framing D4 Framing ESF 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 Switch CDM 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 DR23W 10.Possible Multiplexed Connections Statistical Multiplexing Local Exchange Trunks TrunkingApplication Tie Trunks Release Link Trunks RLTs Special-Access TrunksAuxiliary Trunks Miscellaneous Trunks Connectivity Remote Access TrunksHost-Access Trunks Advanced Private Line Termination Aplt Trunks Signaling Types Administration OptionsSystem 85/G2 Administration Trunk Type Signaling Protocols DS1 Options System 75/G1 AdministrationComm Type Group Type Trunk Tables Interface Circuit Trunking 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 DCS System 75 and Generic 1 UDP Package System 75 and Generic 1 PNA Package DIMENSION, System 85, and Generic 2 Multipremises Package Network Call Processing Distributed Communications System Routing 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 call Analyzing the Dialed Number Automatic Route Selection Communication 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 Networks 2TANDEM TIE Trunk Networks Attendant Lines ⎜ Main Satellite ⎜ Trunks Main-Satellite Conﬁguration MS/T Configurations Main-Tributary Conﬁguration MS/T Features Networking Package Multipremises with ETA Main Networking Package PNA, ETN Routing Outgoing Calls Routing Incoming Calls Engineering Considerations Other Routing Capabilities Interactions 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 Service Main-Satellite/Tributary Networks Distributed Communications System Clusters Distributed Communications System DCS DCS Links Switch Node CapacityDCS Clusters Signaling Link Protocol Signaling LinksSwitch Physical Links ⎜Logical Channels/Link Signaling Link Speed Transmission 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/MPDM System 75/G1 Signaling Channel DCP System 85 or Generic 2 G2 to System 85 or G2 Mtdm Modem 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 Features Automatic Circuit Assurance Attendant Control of Trunk Group Access⎜ ACA Alphanumeric Display Calling Number Display Class-of-Service/Restriction DisplayTrunk Group Busy/Warning Indicators Busy Veriﬁcation of Terminal Lines Automatic Callback on Busy or No Answer Transparent Voice Terminal FeaturesAlerting-Distinctive Ringing Leave Word Calling LWC Without AP Call Coverage ToneCall Forwarding Call Waiting Call Transfer/Conference Audio Information Exchange Audix Features Transparency 20.AUDIX in a DCS Network Definity PBX ⎜ Feature 22DISTRIBUTED Communications System DCS Distributed Communications System, Issue 3 Administration Considerations Dimension PBX Data Connectivity AN Overview Communications Protocols Data Communications Variables Digital PBX Public Switched Network Pooled Modem Synchronous vs. Asynchronous Analog vs. Digital Simplex vs. Half-Duplex vs. Full-Duplex ∙ ∙ ∙ Transmission Speed Parallel vs. Serial Type of Communications Channel Creating Switch Packet vs. Circuit Switches Channel Assignment Dial-up vs. Dedicated Connections Channel Information Bearer vs. Signaling ChannelsTransmission Mode Changes and Modem Pools Terminal Dialing Special Data Features Data Hot Line ⎜Data Services FeaturesData Call Setup From a Voice Terminal Computer Dialing Data Only Off-Premises Extension Data ProtectionData Privacy Data Restriction Off-Premises Data-Only Extension Conﬁgurations Data Communications Capabilities 2DATA Communications Capabilities Protocol Converters DTE ConnectionsDTE Compatibility PC/PBX or PC/ISDN Terminal Emulators Voice Terminal Adjunct Data Modules DCE PossibilitiesData Modules Modems Data Module CharacteristicsStandalone Data Modules ADUs DTE Connections Dtdm PC/ISDN ⎜ PC/PBXPC/PBX ADM Modem 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 LAN Local 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 Backup Public Data Networks Accunet Packet ServiceAPS Access Public and Private Data Network Connections SDS and Sddn Applications Circuit-Switched Public Data Networks Public 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 Processing 8DATA Communications Configurations Reference Related DocumentsGeneral Operation 2RELATED Documents Related Documents Administration Dimension System 75 and Generic 6RELATED Documents System 85 and Generic ServiceSales 8RELATED Documents Sales 10RELATED Documents Need for Synchronization Synchronization of Digital Facilities Figure 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 Misf System 75 and Generic 1 Synchronization Architecture System 75 and Generic 1 Synchronization Software Operation Figure B-6.Tone-Clock Synchronizer Nonduplicated, Generic Criteria for Switching Back to the Primary Reference Criteria for Switching to the Secondary Reference External Synchronization Clock CROSS-CONNECT B25A Cable Output Figure B-9.External-Clock Interface Network Synchronization and Engineering Selecting a Timing Source for the Switch Rule Internal Reference Selection Rules Example 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 Rules Fact 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 Reference Trunk-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 Reference Trunk-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 Capabilities Auto or Automatic-outgoing Alerting SignalsAPLT-Advanced Private Line Termination Auto or Automatic-incoming Cut-Through Mode of Operation Ccsa or Common Control Switching ArrangementCX Signaling or Composite Signaling Customer Provided Access Delay-Dial Start-Dial Ddsd Delay-DialDelay-Dial Incoming Delay-Dial Outgoing Dial-Pulse Derived E&M Lead SignalingDesigned Trunks Dial Repeating Tie Trunk Standard or Type 1A and Type I compatible or Type 1B Direct AccessEpscs or Enhanced Private Switched Communications Service Lead Signaling or Ear & Mouth Signaling FX or Foreign Exchange ETN Trunking Facilities Glare Detection Glare ResolutionGlare Immediate Start Incoming Ground StartHigh-Usage Trunk Group Immediate Start Intertandem Trunk Interdigit Time-outIntermediate High-Usage Trunk Group Intermachine Trunk IMT Main-Satellite Trunks Out-of-Band SignalingParty Test Signal Main PBX Signal Converter Reverse BatterySF or Single Frequency signaling Senderized Mode of Operation Supervisory Signaling Signaling TypeSpecial Access Connections Stop-Go Signaling Type of Outpulsing Touch-Tone SignalingTrunk Type or trunk group type Type of Dialing Wink-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 PBX GROUP/CALL Type Switch B IN/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 Side Other 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 Layer Table D-1.Some Ccitt Digital Standards Ccitt X.26 RS-423A FED-STD Table D-2.Some Ccitt Analog Standards Table D-2.Some Ccitt Analog Standards CCITT-ISO Other Common Standards EIA AT&T Protocols Data Modes Data Mode CapabilitiesDigital Multiplexed Interface Description Applications Control 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 Frame Lead Definitions SBB SCFSCB SBA CH/CI RL/CG RSA SDASTA RDA PND DPRACR CRQ DDB 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 CSU FEP ETAETN FAX NCP MpdmMS/T Mtdm Teho SDNSMT SNA AB-6ABBREVIATIONS AVD GlossaryACU ADM ADS Routing AAR Also high-volume tandemAudix Standalone Automatic Alternate Message-oriented signaling Service BccosBipolar signal Bit-oriented signaling CPU BSCCcitt CPE CcisCOR COS See data communications equipment See network channel-terminating equipment See bit rate Dciu linkDCP DCS DCS cluster DCS node DDD DDC See digital telephone DS1 DCS DMI-BOSDMI-MOS DMI/MOS Framing format Extended trunk access Error-free secondESS electronic switching Communications systems and switch BX.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 network NAU Ncte PAD PDM PVC Protocol converter PC 921, and signaling system numberRemote access trunk Robbed-bit signaling Sdlc TDM UNP UCD Telecommunications Service Wats trunkTelecommunications Service Wats Wide Area Index 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 2-4,2-7,2-8,2-14plan DAC 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-20frame DS1-Contd Mode 1-15,1-16,1-42,2-13,9-1MOS6digitizer DMI 1-14, D-11 Gateway 7-2 D4 1-24, 1-27ESF 1-24, 1-27 FRL 2-10, 2-13 ETN 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 1-36,2-3,5-14 DS1 1-13,1-16,1-18 PAD 7-2,8-21PCM 1-5,1-7,1-14,1-18,B-1 Analog 1-7,9-2trunk RS-232C1-13,6-3 RS-232C1-13,D-9Physical layer 1-11,1-15,D-2,D-9 PRI 1-13, D-11 Intelligent main 2-4, 4-4, 4-7 RNX 2-10Subnet trunking 2-11, 2-14, 4-9 1-39, C-3, C-5, C-6 ﬁnal 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 2-11,6-23 Auxiliary 1-10, 1-35 Uniform dial plan 2-5, 2-8, 2-9Analog 1-9 Uniform numbering 2-8, 5-1, 5-5 IN-12 Index