System 25 Digital Switch | AT&T AT&T manual

SECTION 3—FUNCTIONAL DESCRIPTION

This section describes how the digital switch and the software of System 25 provide control and switching.

Digital Switch

Figure 3-1shows a sehematic diagram of the System 25 digital switch. The basic switch hardware consists of the following:

●Common Control

—Memory Bus

Call Processor Circuit Pack (CP)

—Memory CP.

●Switching Network

Time Division Multiplex (TDM) Bus

—Port Circuits

—System Resource Circuits: Service Circuit, Tone Detector, and Pooled Modem.

COMMON

C O N T R O L

MEMORY BUS

CALL

MEMORY

PROCESSOR

TDM BUS

SWITCHING NETWORK

PORT

CIRCUITS

TRUNKS,

VOICE TERMINALS



	SERVICE			TONE			POOLED
	CIRCUIT			DETECTOR			MODEM

SYSTEM RESOURCES

Figure 3-1. System 25 Digital Switch

3-1

Image 285

AT&T AT&T manual System 25 Digital Switch

Contents

AT&T System To Order Copies of this Document Refer to Document Number 1987 AT&T All Rights Reserved Means of Connection Notification to the Telephone CompanyRepair Instructions Rights of the Telephone Company Private Line ServiceHearing AID Compatibility FCC Registration Information FCC Warning Statement Overview Contents Section Organization Overview Merlin System 25 Description System 25 Block Diagram Safety Call Handling CapabilitiesBusiness Communications Needs Incoming Business Communications DidPDC Outgoing Business Communications Internal Call Movement Data Communications Page Growth & Rearrangement Page Conclusions Smdr List of Figures BIS StarlanSAT LED Description Administration RequirementsConsiderations Interactions Feature Name Type System Features Data Features Network FeaturesFeature Name Feature Feature Name SINGLE-LINE Multiline Terminal Button Label † Station Features Feature Name Console Button Label † Type Attendant Features Account Code Entry Interactions Attendant Call Extending Selector Console optional Interactions Call Coverage/Direct Group Calling DGC If Attendant CAMP-ON None Attendant Cancel Direct Trunk Attendant Console Attendant CONSOLE, Direct Trunk Position Busy Dual Console Operation System Assign Primary Secondary Attendant Direct Trunk Attendant Console Connections Fixed Buttons Figure Attendant CONSOLE, Switched Loop Attendant Message Waiting Attendant Message Waiting Used by Programmable Feature Buttons Figure Display Figure DSS Console Buttons and Display Switched Loop Operation Placing a Call on a Loop Button Answering a Call on a Loop Button Ringing Call Types Call Originations Attendant Features Switched Loop Attendant Console Connections Attendant Direct Extension Selection Model 23A1 Attendant Direct Extension Selector Console Considerations Attendant Direct Extension Selector Console Connections Call Information Display Attendant Display V2 Slac Only Incoming did call Incoming call from a system userIncoming coverage call Returning parked call Call from console to system userOutgoing trunk call Inspection Mode Conference set up by attendantConference 3 Conference 4 Timer Functions Attendant Forced Release V2 Slac Only Join Only Attendant Message Waiting Systems with Direct Trunk Attendant Consoles Dtac Systems with Switched Loop Attendant Consoles Slac Call Coverage Administration Requirements Automatic Release Manual Release Interactions Attendant Return Coverage on Busy Administration Requirements Attendant Return Coverage on DON’T Answer Administration Requirements Attendant Source and Destination V2 Slac Only Attendant Splitting ONE-WAY Automatic Systems Technician Automatic Intercom Administration Requirements Automatic Route Selection ARS ARS Flow Chart FRL ARS Routing Pattern Table Automatic Route Selection Flow Chart Sheet l Automatic Route Selection Flow Chart Sheet 2 0f Considerations ARS Hardware Requirements Automatic Route Selection Routing Pattern BUSY-TO-IDLE Reminder Call Accountability Call Accounting Page Facility Code #190-#199 is identified in this field Call Accounting System CAS CAS Models 200, 300, 500, CAS ModelPage CAS Model Stations Account Codes AT&T Call Accounting Systems DUR FAC STN Account PDC Date Time Column Number Ascii Character Description Valid Position Characters 12. Smdr Call Record Header Format Ascii Character Description Position Z21OA Adapt 15. Smdr Output Equipment -On-Premises Switched Connections 16. Smdr Output Equipment-Off-Premises Direct Connections 17. Smdr Output Equipment-Off-Premises Switched Connections Standard Group Coverage DGC Group Coverage V2 only Page Interactions DGC Group Coverage V2 Only Administration Requirements Standard Group Coverage Sent to coverage Administration Requirements DGC Group Coverage V2 Only Call COVERAGE-INDIVIDUAL Call Coverage -Group Unanswered Call Following Forwarding Interactions Call Park Considerations Attendant Selector Console Assign Call Park buttons Group Call Pickup Directed Call Pickup Administration Requirements Call Progress Tones Facility Access Restriction Outward RestrictionToll Restriction ARS Restriction Hardware Requirements Voice call V2 only Data call or place Data call Options Options Current DefaultEXit Change options View options Hangup Option Definition Partial List of Permissible Data Port TN726 Options Host Modem Computer Users 18. Communications Access Manager Architecture Page Multiline Voice Terminals Single-Line Voice Terminals101 102 Extended Stations An Multiline Voice Terminals except Slac Switched Loop Attendant ConsolesAll Multiline Terminals 103 104 Data Call Setup Data Endpoints DTE Devices106 Data Terminal Without Ascii Keyboard Ascii Data Terminal With Keyboard107 Analog Data Endpoint Host Computer EndpointDCE Devices 108 Data Call Processing Modes Data Endpoint States Controlling Features Connecting Configurations 111 Dialing Correction Dialed CharactersPause 112 Call Disposition End-to-End SignalingAnswering Endpoint 113 114 115 Interactions End-To-End Signaling See above text 116 Dial Code Assignments PDC to Voice Terminal Association Voice Terminal Directed FeaturesData Dial Codes DDCs Direct Inward Dial did Number Assignments 118 119 20. Dictation System Connections FCC Registered 120 21. Digital Tape Unit 121 122 123 124 Transfer For 125 126 23. Delay Announcement Equipment Connections FCC Registered 127 128 129 130 Access to Paging Zones and DGC Groups 131 132 133 134 Activating Expert Mode Making a Data Call135 Dial Activating the Third-Party Call Setup FeatureUser Changeable Options Examples Command MY Command PEInteractions Command Mode 137 138 Conference 139 140 24. External Alert Connections 141 25. Supplemental Alert Adapter Connections Calls Eligible for Hands-Free Service BIS and Hfai Voice Terminals142 Voice Terminals with HFUs Voice Terminals without HFUs143 144 145 500A/502A Headset Adapters 146 MET Headset Adapter 147 148 149 150 151 152 153 154 Prime Line Preference Ringing Line Preference155 156 Preselection LED Indications L-USE IndicationsUse Line Status Meaning Red LED Green LED 157 158 159 Message CENTER-LIKE Operation V2 Slac Only Console ConfigurationsMessage Center Call Types 160 161 Attendant Message Waiting Call Coverage Message Waiting162 163 Station-To-Station Message Waiting 164 165 Calling Restrictions 166 167 168 30. Music-On-Hold Equipment Connections FCC Registered 169 31. Music-On-Hold Equipment Connections Non-Registered 170 Directed NS 171 Trunk-Answer-from-Any-Station 172 173 AT&T 174 32. Delay Announcement Equipment Connections FCC Registered 175 176 177 178 179 180 181 Calls Placed to a PDC 182 Calls Placed to a Floating PDC 183 Direct Station Selection 184 185 186 187 Facility 188 189 190 35 B Emergency Transfer Unit ETU 192 36. Emergency Transfer Unit Connections 193 37. Multiple ETU Arrangements Char Used in Repertory Dialing Numbers Special CharactersCHAR. Used in Personal Speed Dialing Numbers 194 Char Used in Personal Speed Dialing Numbers Transmits an actual195 To Program a Number by Using a Code To Program a Number by Using the Switch196 197 198 199 200 201 202 203 204 205 Speaker 4A Speakerphone System S101A/S102A Speakerphone PEC 3163-HFU207 38. Speakerphone Adjuncts S102A 209 210 211 41. Speakerphone Connections For 12-Button MET Sets CHAR.FUNCTION System Speed DialingChar Function 212 213 Personal Speed Dialing 214 System 25 Starlan Network Access Access Access215 Communications Access Manager CAM Starlan Interface Circuit Pack216 System 25 View of a Starlan Network Starlan Network View of SystemCalls from System 25 to the Starlan Network 217 218 Wiring ZTN78 219 220 Individually Administrable default Administrable ParametersCommon Administration default ATL Adapters Circular Hunting Example Linear Hunting ExampleCombinational Hunting Example 222 223 Call Coverage Station 224 225 Centralized Administration 226 Backspace Return SAT Connection Information227 228 45. Model 703 System Administration Terminal 229 TYPICAL-103A Connection Block 230 231 48. SAT On-Premises Switched Connections 232 49. SAT Off-Premises Direct Connections 233 50. SAT Off-Premises Switched Connections System Errors And Alarms System MaintenancePermanent System Alarms Error s Error Logs Automatic Maintenance Tests235 S c r i p t i o n Tandem TrunkingTrunk Number C o n d A t i o n 236 237 N s i d e r a t i o ns TestT e r a c t i o ns 238 Voice Terminal source THIRD-PARTY Call SetupData Terminal source 239 240 Setting Up a Third-Party Call Administration Requirements Data Port Expert ModeAT&T Starlan Network Access T e r a c t i o ns Call Coverage 242 TIE Trunks 243 Touch-Tone Dial Pads TOUCH-TONE and Dial Pulse ServicesTouch Dial Pads 244 245 T e r a c t i o n s 246 Transfer to Data Data Call Origination Using Transfer to DataData Call Preindication 247 248 249 Trunk Groups C i l i t y N s i d e r a t i o n sS t r i c t i o n s e e Calling Restrictions 250 251 252 TRUNK-TO-TRUNK Transfer User Changeable Options User Changeable Options Definition253 51. Command Mode Menu Tree Viewing Options Changing Options-General255 Changing Data Port Speed EXit Low256 257 Interactions Expert Mode 258 Virtual Facilities A R a C T E RF U N C T I O N Examples of Virtual Facility Numbers259 Accessing a Virtual Facility Example260 261 TDM ATLMET List of Tables System 25 Digital Switch Digital Switch Call Processor Circuit Pack ZTN82 or ZTN128 Common Control Call Processor ZTN82 or ZTN128 Circuitry Interrupt Level Timing and Control Logic Circuit Memory Circuit Pack ZTN81 or ZTN127 TDM Bus Time Slot Generation Not a Timing Diagram Switching Network Electrical Characteristics Physical Characteristics Time Slot No Function TDM Bus Diagram -Three Cabinet System Port Circuits SINGLE-LINE Voice Terminals SMD Asynchronous Data Unit CAS Call Accounting System Translated, and yellow circuit busy Port Circuit Pack Common Circuitry Ground Start Trunk ZTN76 Unique Ground Start Trunk ZTN76 Circuitry Loop Start Trunk ZTN77 Unique Loop Start Trunk ZTN77 Circuitry 10. Unique Tip Ring Line ZTN78 Circuitry Page Port Circuits ATL Line ZTN79 11. Unique ATL Line ZTN79 Circuitry Data Line TN726 12. Unique Data Line TN726 Circuitry MET Line TN735 13. Unique MET Line TN735 Circuitry 14. Unique Analog Line TN742 Circuitry Analog Line TN742Page Did Trunk TN753 15. Unique did Trunk TN753 Circuitry Tie Trunk TN760B 16. Unique Tie Trunk TN760B Circuitry Signaling Type Summary Signaling Transmit Receive Type ON-HOOK OFF-HOOKTN760B Tie Trunk Preferred Signaling Formats Auxiliary Trunk TN763 18. Unique Auxiliary Trunk TN763 Circuitry Network Starlan Interface ZTN84 System Resources Service Circuit ZTN85Saki On-BoardPage 19. Service Circuit ZTN85 Tone Detector TN748 20. Tone Detector TN748 Circuit Pooled Modem TN758 Capability Data Module ModePage Administrative Software Switched Services SoftwareMaintenance Software Memory Allocation Software Partitioning Memory Circuit PackCall Processor Circuit Pack Step-By-Step Call Description Port Circuit Packs 22. System Software Partitioning On the terminal Hfai ListADU SIP Madu System Cabinets J58901A1 Hardware Description System 25 Cabinets J58901A-Three Cabinet System System Cabinet J58901A-Rear View Cabinet 1 Control and Port Circuits Cabinet Address PlugCabinets 2 and 3 Port Circuits System Circuit Pack Configurations Total Port Circuit Packs Per System Required Circuit Packs Circuit PacksOptional Circuit Packs System Resource Circuit Packs Station Port Circuit Packs Circuit Pack Compatibility Trunk Port Circuit Packs Circuit Pack Features Title Circuit Number Circuit Pack Type Ports System Circuit Packs Single-Line Voice Terminals Voice TerminalsModel 500 Series PFT Terminal Circuit Pack Type Model Description Interface Summary of Voice Terminals554BMPA ZTN79 Mode1 2500 Series Analog Voice Terminals Model 2500 Series Mode1 7101A Analog Voice Terminal Model 7101A MD PEC 3170-00M Speakerphone Speakerphone Voice Terminal Single-Line Voice Terminal Connection Information Feature Operations 7300H Series Voice Terminals Multiline Voice Terminals Button Voice Terminal 7302H01D PEC Button Voice Terminal 7302 HOlD Button Voice Terminal 7303H01D PEC Button Voice Terminal 7303HO1D Button Voice Terminal 7305H01D MD PEC Button Voice Terminal 7305HO1D MD Button Deluxe Voice Terminal 7305H02D PEC For General UseFor Use as a Direct Trunk Attendant Console 10 -Button Deluxe Voice Terminal 7305H02D Hfai 11. BIS Voice Terminal 7305H03B Feature Buttons only 12 have associated LEDs 12. BIS Voice Terminal with Display 7305H04B For Use as a Switched Loop Attendant ConsolePage 13. Hfai Voice Terminal 7309HO1B Ten Button Multibutton Electronic Telephone MET 2991 C/D05 14. Ten Button MET Set 2991C05 Ten Button MET With Built-In Speakerphone 2993C04 15. Ten Button MET With Built-In Speakerphone 2993C04 Twelve Button MET Set 7203M 16. Twelve Button MET Set 7203M Voice Terminal Adjuncts Multiline Voice Terminal Connection Information Supplemental Voice Terminal Power Supplies Voice Terminal Adjunct Power SuppliesVoice Terminal Adjunct Connection Information Unit Output For USE with Asynchronous Data Units AD US 17. Asynchronous Data Unit ADU ADU Connection Information Unit PEC Feature Asynchronous Data UnitsZ3A1 Uninterruptible Power Supply Optional Power Equipment AC Power Line Surge Suppressor 346 Modular Bulk Power SupplyTrunk Access Equipment TAE 18. Trunk Access Equipment TAE Connections Station Interconnect Panel SIP 617A PanelAdapters 19 a Station Interconnect Panel 20. Typical SIP Connections Connectivity Figures 21. On-Premises Single-Line Voice Terminal Connections 22. Out-Of-Building Single-Line Voice Terminal Connections SINGLE-ENDED 25 Pair Cable A25D 7300H Type Voice Terminal Ground Wire 26. Ten Button MET Set Connections TYPICAL- 103A Connecting Block ZTN78 TIP Ring Line CP 103A Connecting Block 30. Typical Madu Connections 31. Z3A1/2/4 ADU Local Power Connections Technical Specifications Total Hardware And Software Parameters Hardware And Software Parameters Contd Traffic Data Simultaneous Unit Loads Note Unit LoadsEquipment Circuit Unit Load Pack PER Port ZTN79 BIS Supporting Gauge Wire Circuit Cable Distance LimitationsPack Feet Meters ZTN78 Pack Feet Meters 5106mm Data Rate Gauge Wire Data Terminals RS-232 Connected To Asynchronous Data UnitsFeet Meters Lamp Signal Indicator Lamp SignalsTones Tone Frequency Data Terminal Ports Note Station Type Circuit Pack Data Terminal Specifications Data Terminals Data Requires Z3A1 TerminalZ3A4 ADU REN Dtmf Station Type Circuit Pack Specifications Port Specifications Contd Voice Terminal Ports Contd Trunk Ports Trunk Type Circuit Pack Specifications Ground Start Recommended Central Office Trunk Facilities Calling TrafficVoice Light Medium Heavy Terminals Traffic Signal Level Distortion Level Analog Transmission CharacteristicsLoss Connection Type Loss Connection Bandwidth 64 Kbits Steady State Noise Level Loop ResistanceImpulse Noise Single Frequency Return Loss Talking State Floor Plans And Layouts Environmental Requirements Typical System 25 Equipment Area Floor Plan Typical System 25 Equipment Area Elevation Plan Wall Space Requirements Temperature and Humidity Air Purity LightingElectrical Noise RFI Single Cabinet System AC Power Requirements AC Power Distribution Multiple Cabinet System Lightning Protection Grounding Part Parts Listed by PEC Part of 62512 62512 62512 Merlin VTApparatus Code Comcode ZTN76 Z3A5 ATL ADU MOH 10B ETUZ3A4 ADU CAM PEC Description Apparatus CodeStarlan Network NEU 500BMPA PEC Description Apparatus Code Comcode Merlin Hfai VT S C R I P T I O NMerlin BIS VT Irob CPU/MEM PEC Comcode PEC Description Parts Listed by Comcode M C O DE PEC Description Apparatus Code Merlin BIS M C O DE P E C Description Apparatus Code Merlin Hfai 105341382 1020-S91 AT&T Starlan Network Comcode PEC Description Apparatus Code Supplementary Material Basic Manuals Descriptions of Basic Manuals Reference Manual Planning ManualTerminal Operations Manual User Guides 700 Series Analog Voice Terminals AdministerAppearance Asynchronous Data Transmission Auxiliary Trunk Auxiliary EquipmentBit Binary Digit Bridge Bridging Common Control Switching Arrangement Ccsa Class of Service COSBus, Time Division Multiplex CCS Hundred Call Seconds Coverage Call ConsoleCoverage Path Coverage Point Data Module Delay-Dial Tie TrunkData Terminal Equipment DTE Digital Data Endpoints Feature Button FeatureFacility physical Foreign Exchange FX Immediate-Start Tie Trunk Home Numbering Plan Area Code HnpaIn-Use Lamp Intercept Tone Modem Pooling Multifeature Single-Line Voice TerminalMultilane Voice Terminal Multiplexed Peripheral Equipment ParameterPersonal Dial Code Pickup Group Protocol Random Access Memory RAMPublic Network Queue Switchhook SwitchSoftware Split Tie Trunk Wide Area Telecommunications Service WatsTime Division Multiplex Bus Tone Ringer Write Operation Service 10-1 Index 10-2 Line Contd 10-3 Starlan Network 10-4