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AT&T 7500 series, 7100 series, 2500 series, 7200 series, 7400 series Figure D-1.OSI Reference Model

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

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D-4COMMUNICATIONS PROTOCOLS

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Figure D-1.OSI Reference Model

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AT&T 7500 series, 7100 series, 2500 series, 7200 series, 7400 series, 7300 series manual Figure D-1.OSI Reference Model

Contents

Definity Communications System Page Contents Multiplexing Outside the Switch Communication System Networking AN Overview Tandem TIE Trunk Networks Distributed Communications System DCS Data Connectivity AN Overview Special Data Features Data Communications Capabilities Data Communications Configurations Related Documents Synchronization of Digital Facilities Trunking Terms and Capabilities Communications Protocols GlossaryIndex List of Figures DSU Mpdm Figure B-1 Options for Synchronization Figure B-11 External and Internal Reference Levels List of Tables BCC EIA RS-232C V.28 LEADS/DEFINITIONS EIA RS-232D V.28 LEADS/DEFINITIONSEIA RS-449 V.24 LEADS/DEFINITIONS EIA RS-366 LEADS/DEFINITIONS Xvi Contents About this Document Prerequisite Skills and KnowledgeDocument Organization Part ∙ Glossary ∙ Index HOW to Make Comments about this Document AT&T Xx about this Document Introduction to Connectivity 2INTRODUCTION to Connectivity Transmission Types Analog TransmissionDigital Transmission Analog-to-Digital Conversion Analog VS. Digital 6TRANSMISSION Types Entering the Switch Transmission StatesVoice Transmission 8TRANSMISSION States Digital Switch Exiting the Switch ⎜ Module Circuit Packs Data Transmission Protocol Layers 12TRANSMISSION States Originating Switch Destination Protocols Used Layer 1 Protocols Layer 2 Protocols Protocol States ⎜DMI Mode Code Connectivity Rules 16TRANSMISSION States Multiplexed Communication Types of MultiplexingFrequency-Division Multiplexing Time-Division Multiplexing Statistical Multiplexing Multiplexing Over DS1 Facilities Line Coding Alternating Mark InversionZero Code Suppression ZCS Line Coding B8ZS Line Coding Signal Inversion Restricted ⎜ Unrestricted ⎜ DMI 7Data-Module Capabilities Part 2 D4 Framing Framing Signaling D4 FramingESF Framing Robbed-Bit Signaling 24th-Channel Signaling ⎜ Channels 24th Channel ⎜ 24th ChannelESF ⎜ Frame No Trunk Types/Destinations ⎜ Signaling Types ⎜ DMI-BOS⎜ Isdn PRI Multiplexing Outside the Switch Multiplexing onto T1 Trunks CDM CEM Host Digital DMI PBX Compressing the Signal Getting the Signal Ready for the Central OfﬁceAltering Channel Assignments on T1 Trunks Multiplexing with Microwave Microwave System T1 Trunk CapacityDR23N DR18M DR18W DR23W Demultiplexing 10.Possible Multiplexed Connections Statistical Multiplexing Trunking ApplicationLocal Exchange Trunks Tie Trunks Special-Access Trunks Auxiliary TrunksMiscellaneous Trunks Release Link Trunks RLTs Remote Access Trunks Host-Access TrunksAdvanced Private Line Termination Aplt Trunks Connectivity Administration Options System 85/G2 AdministrationSignaling Types Signaling Protocols Trunk Type System 75/G1 Administration Comm TypeGroup Type DS1 Options Interface Circuit Trunk Tables 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 ⎜ Network Type S75/G1 S85/G2 Package PECDCS Software Capabilities System 75 and Generic 1 UDP Package DIMENSION, System 85, and Generic 2 Multipremises Package System 75 and Generic 1 PNA Package Distributed Communications System Network Call Processing Internal Dial Plan Uniform NumberingRouting the Call DAC + EXT To ARS Auxiliary Call Information Automatic Alternate Routing Selecting a Routing Pattern ∙ RNX ∙ Where the trunk group appears in the list of preferences Selecting a Trunk Group∙ The FRL of the call Modifying the Digits Automatic Route Selection Analyzing the Dialed Number Communication System Networking AN Overview To AAR Selecting the Routing Pattern Network Administration Networking Feature ParametersPrivate Network Trunks ⎜ Maap ⎜ Vmaap System Definity Feature PBX 20COMMUNICATION System Networking AN Overview Tandem TIE Trunk Networks Interactions with Other Networks 2TANDEM TIE Trunk Networks Attendant Lines ⎜ Main Satellite ⎜ Trunks MS/T Configurations Main-Satellite Conﬁguration Main-Tributary Conﬁguration MS/T Features Networking Package Multipremises with ETA Main Networking Package PNA, ETN Routing Incoming Calls Routing Outgoing Calls Other Routing Capabilities Engineering Considerations Interactions Page ETN Configurations ETN Trunks Page Access and Bypass Access Tie Trunks Features Off-Net TrunksUniform 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 Distribution Distributed Communications System Clusters Main-Satellite/Tributary Networks Distributed Communications System DCS Switch Node Capacity DCS ClustersDCS Links Signaling Links Switch Physical Links ⎜Logical Channels/LinkSignaling Link Speed Signaling Link Protocol Transmission Media Direct Link DCS Connections Linkage Design Distributed Communications System DCS DCS Signaling Link Connections Equipment Distance LimitationMTDM/MPDM System 75 or Generic 1 G1 to System 75 or G1 System 75/G1 Signaling Channel DCP Mtdm System 85 or Generic 2 G2 to System 85 or G2 Modem System 75 or Generic 1 G1 to System 85 or Generic 2 G2 RS232C to RS449 Conversion Dciu Dimension Signaling Links Transparent FeaturesTransparent Attendant Features Attendant Call Waiting Attendant Control of Trunk Group Access ⎜ ACAAlphanumeric Display Automatic Circuit Assurance Class-of-Service/Restriction Display Trunk Group Busy/Warning IndicatorsBusy Veriﬁcation of Terminal Lines Calling Number Display Transparent Voice Terminal Features Alerting-Distinctive RingingAutomatic Callback on Busy or No Answer Call Coverage Tone Call ForwardingCall Waiting Leave Word Calling LWC Without AP Audio Information Exchange Audix Features Transparency Call Transfer/Conference 20.AUDIX in a DCS Network Definity PBX ⎜ Feature 22DISTRIBUTED Communications System DCS Administration Considerations Distributed Communications System, Issue 3 Dimension PBX Data Connectivity AN Overview Data Communications Variables Communications Protocols Digital PBX Public Switched Network Pooled Modem Analog vs. Digital Synchronous vs. Asynchronous ∙ ∙ ∙ Simplex vs. Half-Duplex vs. Full-Duplex Parallel vs. Serial Transmission Speed Creating Switch Packet vs. Circuit Switches Type of Communications Channel Channel Information Bearer vs. Signaling Channels Transmission Mode Changes and Modem PoolsChannel Assignment Dial-up vs. Dedicated Connections Special Data Features Terminal Dialing ⎜Data Services Features Data Call Setup From a Voice TerminalComputer Dialing Data Hot Line Data Protection Data PrivacyData Restriction Data Only Off-Premises Extension Off-Premises Data-Only Extension Conﬁgurations Data Communications Capabilities 2DATA Communications Capabilities DTE Connections DTE CompatibilityProtocol Converters Terminal Emulators PC/PBX or PC/ISDN DCE Possibilities Data ModulesVoice Terminal Adjunct Data Modules Data Module Characteristics Standalone Data ModulesADUs Modems DTE Connections Dtdm ⎜ PC/PBX PC/PBXADM PC/ISDN Modem Pooling Connections DCP TIP-RING 12DTE Connections Data Module Local Area Network Connections LAN TopologyLAN Protocol LAN Connectors LAN Transmission MediaAdvantages of a Communications System in a LAN Environment LAN Access to/from LANs That Use Other Operating Systems Type Operating Gateway PCLAN System Software Local Area Network Connections Remote PC ISN Communication Communication Between the LAN and Other NetworksX.25 Router Type Operating Communications System PackageSNA Gateway Communication System as a LAN Backup 12.LAN/SNA Connectivity Accunet Packet Service APS AccessPublic and Private Data Network Connections Public Data Networks Circuit-Switched Public Data Networks SDS and Sddn Applications Public and Private Data Network Connections MPDM/M1 Public and Private Data Network Connections DTE Mpdm Private Data Networks Terrestrial Private Data Network LinksPrivate Connections Through Accunet T1.5 and T45 MPDM/M1* AMI 28PUBLIC and Private Data Network Connections ⎜AMI Satellite Private Data Network Links Telemarketing Host Connections Isdn GatewayIntegrated 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 Connections Through Public or Private Data Networks File TransfersVideo Teleconferencing Image Processing FAX Transmittal 8DATA Communications Configurations Related Documents GeneralOperation Reference 2RELATED Documents Related Documents Dimension Administration System 75 and Generic 6RELATED Documents Service SalesSystem 85 and Generic 8RELATED Documents Sales 10RELATED Documents Synchronization of Digital Facilities Need for Synchronization Figure 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 Primary Secondary Reference Indicators ⎜ Reference ⎜ IndicatorsRED YEL Good LOS Misf ⎜ Blue RED System 75 and Generic 1 Synchronization Architecture Figure B-6.Tone-Clock Synchronizer Nonduplicated, Generic System 75 and Generic 1 Synchronization Software Operation Criteria for Switching to the Secondary Reference Criteria for Switching Back to the Primary Reference External Synchronization Clock CROSS-CONNECT B25A Cable Output Figure B-9.External-Clock Interface Selecting a Timing Source for the Switch Network Synchronization and Engineering Internal Reference Selection Rules Rule 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 External-Reference Selection Rules Rules 2 Through Availability of Synchronization Sources MisconceptionFact Line-Only Mode DS1/DMI-BOS ANN11 or TN767 Conclusions on SynchronizationUSE of Generic 2 AS a System Clock Reference ISDN-PRI Trunk Facilities Line+Trunk Mode DS1/DMI-BOS ANN35 or TN767 with TN555 DMI-MOS ANN35 or TN767 with TN555USE of Generic 1 AS a System Clock Reference Trunk-Mode ISDN-PRI TN767 Line-Only Mode DS1/DMI-BOS TN767 Trunk-Mode Interface ISDN-PRI + Robbed Bit TN767Trunk-Mode DS1/DMI-MOS TN767 32SYNCHRONIZATION of Digital Facilities Wire Tie Trunk Address SignalingTrunking Terms and Capabilities Frequently Used Terms Alerting Signals APLT-Advanced Private Line TerminationAuto or Automatic-incoming Auto or Automatic-outgoing Ccsa or Common Control Switching Arrangement CX Signaling or Composite SignalingCustomer Provided Access Cut-Through Mode of Operation Delay-Dial Delay-Dial IncomingDelay-Dial Outgoing Delay-Dial Start-Dial Ddsd Derived E&M Lead Signaling Designed TrunksDial Repeating Tie Trunk Dial-Pulse Direct Access Epscs or Enhanced Private Switched Communications ServiceLead Signaling or Ear & Mouth Signaling Standard or Type 1A and Type I compatible or Type 1B ETN Trunking Facilities FX or Foreign Exchange Glare Resolution GlareGlare Detection Ground Start High-Usage Trunk GroupImmediate Start Immediate Start Incoming Interdigit Time-out Intermediate High-Usage Trunk GroupIntermachine Trunk IMT Intertandem Trunk Out-of-Band Signaling Party Test SignalMain PBX Main-Satellite Trunks Reverse Battery SF or Single Frequency signalingSenderized Mode of Operation Signal Converter Signaling Type Special Access ConnectionsStop-Go Signaling Supervisory Signaling Touch-Tone Signaling Trunk Type or trunk group typeType of Dialing Type of Outpulsing Wats Wide Area Telephone Service Trunk Wink-Start IncomingWink-Start Outgoing Suggestions and Helpful Hints Trunking Characteristics Table Signaling Types Switch a Supervision Signaling Tion GenericSystem 85, or Dimension PBX ⎜GROUP/CALL Type Switch B GROUP/CALL Type DOD 23/FX-DOD OUTIN/DID GROUP/CALL Type Signaling 26/WATS 27/WATS OUT28/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 Digital Data ⎜DATA Module Side 103/HOST Access Line Side 104/HOST AccessAnalog Data Modem Side Trunk Side Other 32TRUNKING Terms and Capabilities Communications Protocols OSI Model Physical LayerData-Link Layer Network LayerPage Figure D-1.OSI Reference Model Session Layer Presentation LayerApplication Layer Standard Protocols Table D-1.Some Ccitt Digital Standards Table D-2.Some Ccitt Analog Standards Ccitt X.26 RS-423A FED-STD Table D-2.Some Ccitt Analog Standards Other Common Standards CCITT-ISO AT&T Protocols EIA Data Mode Capabilities Digital Multiplexed InterfaceData Modes Applications Description Control 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 Sldh Lead Definitions SCF SCBSBA SBB RL/CG CH/CI SDA STARDA RSA DPR ACRCRQ PND BBA BBBDDA DDB ⎜ PIN 8LEAD Definitions Networking FEATURES--AVAILABILITY Matrix ⎜⎜ R1 Networking FEATURES--AVAILABILITY Matrix Contd ⎜ NA ⎜ Uniform Numbering ⎜ Plan Note 6NETWORKING FEATURES--AVAILABILITY Matrix Abbreviations CRC CSMCSU DAC ETA ETNFAX FEP Mpdm MS/TMtdm NCP SDN SMTSNA Teho AB-6ABBREVIATIONS Glossary ACUADM AVD ADS Also high-volume tandem Audix StandaloneAutomatic Alternate Routing AAR Service Bccos Bipolar signalBit-oriented signaling Message-oriented signaling BSC CcittCPU Ccis CORCOS CPE See network channel-terminating equipment See data communications equipment Dciu link DCP DCSDCS cluster DCS node See bit rate DDC DDD See digital telephone DCS DMI-BOS DMI-MOSDMI/MOS DS1 Error-free second ESS electronic switchingCommunications systems and switch Framing format Extended trunk access BX.25 DCIU/PI Hdlc Keyboard dialing Kilo bits per second kbps LAN LapdSee basic rate interface See primary rate interface Listed directory number Local area network LANAlso wide area network Local exchange company Ncte NAU PAD PVC PDM 921, and signaling system number Remote access trunkRobbed-bit signaling Protocol converter PC Sdlc TDM UCD UNP Service Wats trunk Telecommunications ServiceWats Wide Area Telecommunications Index Bypass access trunk 1-37,4-7,4-8,5-1,5-4,C-2 IN-2 IndexARS 2-4,2-7,2-8,2-14plan Logical 6-3,D-19restricted 1-20unrestricted Dial access code 2-2,2-5,2-10,2-13,2-17,3-1,4-4 CRC 1-25CSMA/CD 8-13CSUChannel bank 1-9,1-10,1-29,1-30,B-20frame DAC 2-2,2-5,2-10,2-13,2-17,3-1,4-4,4-7,4-8,4-9,6-23 Mode 1-15,1-16,1-42,2-13,9-1MOS 6digitizerDMI 1-14, D-11 DS1-Contd D4 1-24, 1-27 ESF 1-24, 1-27FRL 2-10, 2-13 Gateway 7-2 Statistical 1-17,1-18,1-34 LOS B-9,B-13 LWC 6-18,6-21,6-24DCS 1-36,2-3,5-14 ETN 1-36,2-2,2-8,3-1,4-1,5-1,6-1 PAD 7-2,8-21 PCM 1-5,1-7,1-14,1-18,B-1Analog 1-7,9-2trunk DS1 1-13,1-16,1-18 RS-232C1-13,D-9 Physical layer 1-11,1-15,D-2,D-9PRI 1-13, D-11 RS-232C1-13,6-3 RNX 2-10 Subnet trunking 2-11, 2-14, 4-91-39, C-3, C-5, C-6 Intelligent main 2-4, 4-4, 4-7 Analog 1-3,7-2,7-4 Bypass access 1-37,4-7,4-8,5-1,5-4 T1 carrier 1-6,1-18,1-32TCM 2-11,6-23 ﬁnal 5-2,C-9 Uniform dial plan 2-5, 2-8, 2-9 Analog 1-9Uniform numbering 2-8, 5-1, 5-5 Auxiliary 1-10, 1-35 IN-12 Index