Meridian America 51, 61, 71, 21 User Manual

SL-1

System options

System overview

Standard

21,51,61,71

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SL-1

System options

21,51,61,71

System overview

Publication number: 553-3001-I 00 Document release: 1 .O Document status: Standard Date: January

29,199O

1990 Northern Telecom

System overview 553-3001-l 00

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Revision history

January

29,199O

Standard,

release

1.0

System overview 553-3001-100

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About this document

This document describes the features and services, hardware and software architecture, and the family of products that comprise Meridian 1.

References

See the SL-I planning & engineering guide

Master index

System overview

Installation planning

System engineering

Power engineering

Sparesplanning

Equipment identification and ordering

(553-3001-000)

(553-3001-100)

(553-3001-120)

(553-3001-151)

(553-3001-152)

(553-3001-153)

iii

for

(553-3001-154)

See the list of

line

and trunk circuit descriptions in

the Master index

(553-3001-000) for specific references to lines and trunks.

See the SL-1 installation and maintenance guide

System installation procedures

Circuit pack installation and testing

Installation procedures for telephone sets

and attendant consoles

Extended systems installation

Disk drive upgrade procedures

(553-3001-215)

(553-3001-210)

(553-3001-211)

(553-3001-250)

(553-3001-251)

for

System overview 553-3001-100

iv About this document

General maintenance information Fault clearing Hardware replacement

(553-3001-510)

(553-3001-520)

(553-3001-500)

See the SL-1 XII software guide

for an overview of software architecture, procedures for software installation and management, and a detailed description of all Xl 1 features and services. This information is contained in two documents:

XII software management (553-3001-300)

XII features and services

See the

SL-1

XII input/output guide

(553-3001-305)

(553-3001-400) for a description of all

administration programs, maintenance programs, and system messages.

System overview 553-3001-100

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Meridian 1

The Meridian 1 commitment Advanced features

System architecture

Meridian 1 modular architecture

Control Switching Peripherals

Software architecture

Firmware Software Office Data

Resident Programs

Non-Resident Programs

Hardware architecture

Common equipment

Network equipment

Peripheral Equipment

Power equipment

Product description

Universal Equipment Modules

CPU module (NT8D34)

CPU/Network module (NT6D39)

Network module (NT8D35)

Common/Peripheral Equipment module

Intelligent Peripheral Equipment module (NT8D37) Peripheral Equipment module (NT8D13)

(NTSDll)

9 9

9 10 10 11 11

11 11

13 13

17 31 32

37 39 41 43 45 48 50

System overview 553-3001-100

vi Contents

Remote Peripheral Equipment Carrier module (NT8D47)

InterGroup module (NT8D36AA)

Meridian Mail module (NT6D44)

Pedestal (NT8D27AB) Top cap Expansion kit (NT8D49)

Meridian 1 system options

Meridian 1 system option 21A Meridian 1 system option 21 Meridian 1 system option 51 Meridian 1 System option 61 Meridian 1 system option 71

(NT7DOO)

List of terms

52 54

55 57 57

60 60 62 64 66 68

System overview 553-3001-l 00

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Meridian

Introduction

Meridian 1 Communication Systems are a family of digital multiplex voice and data switching systems built upon a foundation of state of the art digital switching equipment and advanced software program control. Meridian 1

systems provide a wide range of sophisticated voice and data services for both Private Branch Exchange (PBX) and Central Office (CO) applications ranging in size from 30 to 60,000 ports.

A Meridian 1 Communication System is a single source solution to the

complex requirements of today’s business communications environment. In

a single, integrated system, it provides advanced voice features, local

network communications, and sophisticated information services. A

comprehensive open architecture ensures continual growth in capacity and

the capability to address the ongoing needs of business communications and

information management.

The foundation for Meridian 1 Communication Systems is a voice and data

circuit-switched digital sub-system. It is comprised of a central processing

unit, memory store, and a digital switching network that uses time division multiplexing and pulse code modulation techniques. Peripheral interfaces are used to connect a wide array of telephones, trunks, and terminals.

Meridian 1 Communication Systems systems are also designed to

accommodate the rapidly expanding requirements for data communications.

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Building upon the strength of the original SL-1 architecture, significant

system enhancements have been developed for data communications,

including:

area

System overview 553-3001-100

2 Meridian 1

Meridian Modular Telephones, a family of digital telephones that utilize standard twisted pair wiring and support a wide range of data communications options.

Meridian 1 LANSTAR, a 2.56 Mbps local area network (LAN) for Macintosh II and IBM PC compatible computers.

The Meridian 1 commitment

Northern Telecom is committed to meet the needs of our customers by providing systems which guarantee:

Continuing product compatibility

A high degree of component and system reliability

Cost effective, modular packaging

Advanced administration and maintenance capabilities

Ease of installation

Cost effective system expansion and upgrade

Product compatibility

All new products are compatible with the installed base of systems and can

be installed alongside existing equipment. For network enhanced Meridian

SL-1 systems, the upgrade consists of adding X11 release 15 software with a new CPU ROM pack, Superloop Network cards in existing network slots, and one or more Intelligent Peripheral Equipment Modules. For non-

network/GE enhanced Meridian SL-1 systems, an upgrade package is also

available. For more information about extending existing systems, see

Extended systems installation

(553-3001-250).

In addition, Meridian 1 systems now utilize the DS-30 signalling method

used by other Northern Telecom switching products, providing a common signalling scheme throughout the Meridian 1 family and allowing for system growth beyond 10,000 ports without requiring a change in peripheral equipment.

System overview 553-3001-l 00

System reliability

Meridian 1 systems are designed and built to meet the highest standards for reliability, resulting in less downtime and increased system availability. In

most systems, critical system elements are duplicated to guarantee system reliability. There are two identical Central Processing Unit (CPU) and memory circuits in most system configurations, and both CPUs can access both memory circuits. If one CPU or memory circuit fails, the system automatically switches to the standby CPU or memory circuit without disrupting call processing.

Modular equipment packaging

Meridian 1 hardware is housed in modular equipment cabinets that are common to all system elements. These cabinets are called Universal Equipment Modules (UEM). Each UEM has removable front and rear covers with locking latches for easy access to its contents.

UEMs are stacked one on top of another to form a column. Each column

may contain up to four UEMs. Systems are comprised of one or more columns. An Expansion Kit is provided to interconnect the columns in a

multi-column system for compliance with FCC standards for EMI/RFI. At

the base of each column of UEMs is the pedestal The pedestal houses

cooling fans, air filters, a power distribution assembly (including the circuit breakers and power switches) and a System Monitor circuit. At the top of-

each column is a Top Cap assembly which consists of two air exhaust

grilles and a thermal sensor assembly.

Meridian 1 3

Advanced administration & maintenance

An important feature common to all Meridian 1 systems is an advanced

administration and maintenance system. Administration and maintenance

functions can be performed locally or at a remote location. These functions

include service change, reassignment of features, and additions or deletions

of equipment. Meridian 1 systems also provide an automatic in-line

conversion feature which significantly simplifies upgrades of Xl 1 software.

Reconfiguration of system data structures occurs during system reload.

A System Monitor circuit card controls and monitors the status of all power-

related hardware and functions, including column thermal status, power

supply operation, blower operation, power fail transfer, circuit breakers, external rectifiers, batteries, and Uninterruptable Power Supply (UPS) systems. The same system monitor is used for AC and DC powered

System overview X3-3001 -100

.’

4 Meridian 1

systems. A System Monitor is installed in.the pedestal of each column. The System Monitor located in the column containing CPU0 acts as the master system monitor; monitors located in other columns act as slaves. The master polls the slaves and reports their status to the CPU. The master System Monitor is connected to the CPU by an RS232C port located on an

SD1

card. Slave System Monitors are connected to the master in a daisy

chain fashion with an 8-conductor RJ type connector.

System messages reported to the CPU by the System Monitor are output to

the system terminal. System messages include the following types of

information: status or fault indication, hardware type, column number, module number and power supply unit number.

Maintenance and traffic messages are also output to the system terminal. Maintenance messages indicate the results of diagnostic routines and alert maintenance personnel to fault conditions. Traffic messages indicate the load on different areas of the system and the associated grade of service.,

Meridian 1 systems feature an advanced background diagnostic program which reports system status and identifies detected faults. The program automatically restarts where it stopped, following an interruption. Diagnostic routines may also be initiated by maintenance personnel as required.

A new series of circuit cards contain microprocessors which offload processing functions previously performed by the CPU. The on-board microprocessors significantly increase circuit card and system diagnostic capabilities, resulting in improved maintainability. Where possible, hardware switch selection has been replaced with software-controlled selection of circuit card options. The on-board microprocessors also allow for circuit card parameters to be changed without requiring hardware revisions. Parameters are stored on the system disk drive unit, and are downloaded to the circuit card at system reload or upon user command. The new cards also make use of on-board intelligence by reporting their product code, serial number, release number and manufacture location, assisting maintenance and inventory control.

System overview 553-3001-100

Meridian 1 5

Ease

of installation

Every Meridian 1 system is shipped from the factory assembled and

equipped to order. Installation effort is reduced to unpacking and

positioning equipment, plugging in connectorized cables, ‘and adding

customer-specific programming where required.

Ease of expansion

The modular packaging scheme employed by the Meridian 1 family of

products accommodates growth by permitting easy expansion. System expansion simply requires adding one or more UEMs. The modular packaging scheme also provides for low cost, easy expansion from one system type to another. For example, the card cage assembly of a UEM containing CPU equipment for a small system may be removed and replaced with the CPU card cage assembly designed for larger systems. addition, peripheral equipment, which is the bulk of the system investment, is common to all system types and may be retained when

Advanced features

By providing service capabilities defined by software, which can be expanded as needs evolve, Meridian 1 systems offer advanced features and capabilities in an economical, flexible, and maintainable form. In addition.to a wide range of standard voice and data services, Meridian 1 systems also

provide a number of sophisticated communications services and features,

including:

expandi&

ACD

Automatic Call Distribution (ACD)

Electronic Switched Network (ESN)

Call Detail Recording (CDR)

Integrated Services Digital Network (ISDN)

Meridian Mail Voice Messaging

Automatic Call Distribution (ACD) is used when a large volume of incoming calls must be answered by a group of telephones allocated for this purpose. Incoming calls are served on a first-in, first-out basis and are distributed among the available telephones. For more information on ACD, refer to Northern Telecom Publication

features description

(553-2671-100).

Automatic Call Distribution Basic

System overview 553-3001-l 00

..:

6 Meridian

ESN

CDR

The Electronic Switched Network (ESN) group of features supports voice and circuit-switched voiceband data telecommunications for multiplelocation customer applications. ESN applications range from a single network node (combined PBX and network switching system) to a widely- dispersed network with up to 256 locations. For more information about ESN, refer to the ESN Feature Document 6400-886 and to the following Northern Telecom Publications:

ESN: 308-3001-100

BARSmARS: 553-2751-100,553-2751-101

CDP: 553-2751-102

Call Detail Recording (CDR) is a software package that gathers call processing data and produces call records used for accounting and administrative purposes. Call records provide information about the call, such as the time and date the call was placed, the identity of the caller, and the digits dialed. CDR is compatible with all Meridian 1 software generics. For more information,

see Call Detail Recording general description

(553-2631-100).

ISDN

Integrated Services Digital Network (ISDN) is an international specification of standards for digital communications. ISDN provides standard digital interfaces between telephones, terminals, and telecommunication networks. ISDN services are distinguished by two types of access: Primary Rate Access (PRA) and Basic Rate Access (BRA). For more information on PRA,

see ISDN Primary Rate Access product description

Meridian Mail Voice Messaging

Meridian Mail is a comprehensive electronic voice processing system

designed and developed to increase any organization’s productivity by

enhancing telecommunications activities. Meridian Mail provides a wide

array of sophisticated features, including: telephone call answering, voice messaging, automated attendant service, call routing, information mailbox, and interactive voice response applications.

System overview 553-3001-I 00

(553-2901-100).

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Meridian 1 7

Meridian Mail voice messaging eliminates telephone tag and wasted calls

by allowing detailed messages to be exchanged when parties are unavailable

or busy.

Guided by easy to follow prompts, a user can leave messages for

others, retrieve messages, forward messages, and respond to messages with

the touch of a single button.

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System overview 553-3001-l 00

8 Meridian 1

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System overview 553-3001-100

System architecture

Meridian

Control

Switching

1 modular architecture

An important characteristic of Meridian 1 systems is a modular system architecture. It utilizes an efficient and flexible approach, employing modular construction in all areas of hardware and software, and state-of-the- art commercial and custom components. The result is a system which is highly flexible in terms of operational, maintenance, and administrative characteristics. As demands dictate, any module may be enhanced, singularly or in combination with other modules. Each system is organized around three functional areas: Control, Switching, and Peripherals.

The Control complex provides the sequences required by the system to process voice and data call connections, monitor call activity, and perform

system administration, maintenance, and testing. It is composed of two elements: the central processing unit (CPU) which directs lower level subsystems in the hierarchy, and the system memory which stores the operating programs.

The switching function is performed by the network equipment, which interconnects terminal devices for communication with each other. The network architecture is based on the concept of a digital multiplexed loop. A loop is a bidirectional path between Network and terminal device which

transmits voice, data and signalling information.

System overview 553-3001-100

10 System architecture

Peripherals

Peripheral equipment provides the analog and digital interfaces for all peripheral devices, and performs analog to digital conversion of all input

signals before switching is performed by the Network. Additionally,

Peripheral equipment circuits provide the supervisory and transmission

functions needed for trunks connected to the external telecommunications network.

Meridian 1 systems use a star topology for connecting peripheral devices to the switching equipment, an approach which permits uniform distributed wiring methods. This approach provides significant benefits in the area of administration, installation, maintenance and reliability.

Figure 1 Meridian 1 modular architecture

Control

Software architecture

The adaptability of software control provides a complete array of services and features tailored to meet changing requirements.

Call processing, maintenance and administration of Meridian 1 systems are controlled by software programs stored either as firmware programs, as software programs resident in system memory, or as non-resident programs on disk. The information which describes system configuration and associated peripheral equipment is termed office data. This data resides in the system memory and on disk.

Switching

Network Circuits

Peripherals

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System overview 553-3001-I 00

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Firmware

These are fundamental programs consisting of hard-wired logic instructions

stored in Programmable Read Only Memory (PROM) which manipulate

data in the central processor and control input/output operations, error

diagnostic and recovery routines.

Software

Software programs consist of instruction sequences that control call processing, peripheral equipment, administration and maintenance functions. These sequences are interpreted by the fiiware programs into machine instructions. Several generic software programs with optional feature packages are available to satisfy varying requirements.

Office Data

The office data describes the characteristics of the system in terms of configuration and call dependent information such as features and services. Office data is arranged into blocks defining peripheral equipment, system configuration and transient data. These data blocks permit configuration of

Meridian 1 systems to specific customer needs.

Resident Programs

Resident Programs are programs always available in memory during system

operation. Firmware programs control other resident programs and provide

all CPU arithmetic operations. The other resident programs are those which

are automatically loaded into the system memory from the disk drive at

system power-up. Once loaded, these programs remain in memory.

System architecture

I I

Non-Resident Programs

Non-Resident Programs are the overlay programs stored on disk which are

loaded into the “overlay area” of system memory when required to perform

specific tasks. Only one overlay program may be loaded at a time and is

removed from the overlay area when no longer required. Overlay programs

can be loaded automatically, under program control, or manually, via an

administrative terminal.

Once the user has logged into the system, commands for specific overlay

programs are processed by the overlay loader program. When loaded, the

overlay program assumes control. Only one administrative terminal can

input into the overlay arca at a time. More than one device, however, can

System overview 553-3001-l 00

12 System architecture

receive output simultaneously. A terminal may be configured as an input only or

Overlay programs provide the system interface for maintenance, service change, and traffic measurement. Each overlay program is independent and

has its own specific set of commands and formats. Overlay programs may

be run concurrently with normal call processing without interfering with

system traffic. There are five main categories of overlay programs:

Service Change and Print Routines

Service changes do not generally require hardware intervention. Instead, the service administration programs are used to create or modify all aspects of the system from individual feature key assignments to complete system configurations. There are also programs and print routines for retrieving the data from the system to check the status of office data assignments.

Maintenance Diagnostics

These programs are the primary instruments for maintenance purposes. Individual programs are used for automatically or manually testing the CE and PE. The programs may be loaded into the overlay area at the request of maintenance personnel, or as part of a daily maintenance routine automatically initiated by the system at a specified time. In addition, background and signaling diagnostic routines can occupy the overlay area when it is not in use.

output

only device.

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Traffic

All systems are equipped with traffic data accumulation programs. There is also a resident traffic print program which examines the schedules, transfers data from accumulating to holding registers in accordance with schedules, and prints the traffic data. In addition, there is a traffic overlay program which is used to query and modify schedules, options, and thresholds.

Equipment Data Dump

After making service changes, the changes must be transferred to disk in order to save them. When the equipment data dump program is invoked, all

the office data in the read/write memory is written to the system disk. The data dump program is also used to install a new generic version or issue and capture protected data store information which may be changed by the user, such as speed call lists. The program may be invoked automatically during

System overview 553-3001-l 00

a midnight routine or on a conditional basis (i. e. , data dump only occurs if a software service change has been made). It may also be invoked manually via the input/output (I/O) interface to the system.

Software Audit

This program monitors system operation and gives an indication of the

general state of the system operation. The program is concerned mainly with the system software. When a software problem is encountered, the

program attempts to clear the problem automatically.

Hardware architecture

Each Meridian 1 system is composed of the following hardware subsystems:

Common equipment (CE): Provides the device control, software execution, and memory functions of the system.

Network equipment (NET): Performs the switching function under

CPU control.

Peripheral equipment (PE): Provides the interface for line and trunk circuits.

Terminal equipment: Telephone sets and attendant consoles.

Power equipment Provides the electrical voltages required to operate equipment.

System architecture 13

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Common equipment

Common Equipment (CE) consists of one or more Central Processing Units

(CPUs), memory circuits, and mass storage devices which control the

operation of the system. The CE communicates over a common control bus which carries a constant flow of program instructions and data under direct control of the CPU. The digitized speech signals follow a separate path on a network switching bus which allows communications links to be established between any of the peripheral devices.

The Central Processing Unit (CPU) provides the computing power

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essential for entire system operation.

System overview 553-3001-l 00

14 System architecture

Central Processing Unit (CPU)

The CPU performs the control and switching sequences required by the system. The software that directs these functions is loaded into the system memory from the mass storage unit by the CPU. between the CPU, I/O devices, and the system memory over the CPU bus.

The data required by the CPU to perform its control and switching functions is held during system operation in Random Access Memory (RAM) and fed

to the CPU via the CPU bus. The operating data is loaded into the RAM from floppy diskettes on system power-up.

The system memory stores all operating software programs and data unique to the particular Meridian 1 system, including switching sequences, features, class of service information, and quantity and types of terminals.

The Mass Storage Unit provides high speed loading of the operating programs and data into memory.

The Digital Service Circuits provide functions such as dial and ringing tones, and call conferencing capabilities.

The Serial Data Interface (SDI) provides a RS232C communications link for administration and maintenance on either a local or remote basis.

The Network Circuit Cards provide a digital matrix for circuit-switched connections to associated peripheral devices.

Information flows

The CPU function is performed by circuit cards which include Read-Only- Memory fiiware that contains fault clearing programs and instructions to control the loading of system memory from the mass storage unit.

Meridian 1 systems incorporate a CPU design that is identical for most system options.

24-bit data words plus l-bit parity

24-bit linear addressing that permits memory allocation to be assigned on a contiguous basis instead of the 64K pages partitioning referenced above

16M words - subdivided for up to 12M words of physical memory

space and a remainder of 4M words for I/O spaces

System overview 553-3001-100

System architecture 15

asynchronous (handshake) bus operation

16 file registers used to hold address and data for all operations

a sense (interrupt) input line to indicate that a particular device (tape,

TTY, PE) requires action by the CPU

a trap facility which, when activated by an external signal,

causes the

CPU to immediately begin executing instructions starting at a particular address; this facility is used to enter a recovery routine when a fault is detected

Mass Storage Unit

A mass storage unit equipped with two floppy diskettes and/or a Winchester hard disk is used for high speed loading of the resident operating programs and office data into system memory. The loading process is controlled by instructions held in the Read-Only-Memory (ROM) fiiware.

When loading is complete, the diskettes remain in the mass storage unit to provide a non-volatile store for automatic loading purposes in the event of software being erased from memory during a power failure. Non-resident software is loaded from the disk automatically or by manual request when required.

The Mass Storage Interface (MSI) card is designed to interface with

external devices that are compatible with the Small Computer System

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Interface (SCSI). This storage capability is provided by the following hardware configurations:

NT8D68AA Floppy Disk Unit: two 3.5” 1.2 Mbyte floppy disk drives

(providing 2.4 Mbytes of formatted capacity) as a standard system

offering,

NTSD69 AA Multi Disk Unit: a Winchester Hard Disk with 10 Mbytes

of formatted capacity. When this option is equipped, the floppy disks are used for backup and system loading.

System overview 553-3001-100

16 System architecture

Both types of Mass Storage Unit (MSU) are compatible with any Meridian

1 system running Software Generic Xl 1 Release 8 or later. The upgrade procedure involves replacing the Magnetic Tape Transport and associated tape interface with the desired Mass Storage Unit and equivalent Mass

Storage Interface card (MSI) or Floppy Disk Interface (FDI) card. The Mass Storage Unit requires the identical space required for the magnetic

tape unit, See

information about disk drive upgrades.

Disk drive

upgrade procedures

(553-3001-251) for more

Input / Output (I/O)

llnterfaces

There are various methods of communicating with Meridian 1 systems. A

family of Serial Data Interface (SDI) circuit cards provides from one to four

communication channels which conform to EIA Data Interchange Standard

RS-232-C. I/O addressing is under switch control of the

SD1

card and allows up to 16 RS-232-C compatible devices, such as a terminals, to communicate with the system. The devices are used to input commands and/or receive responses from the system during administration and

maintenance procedures.

Memory

Firmware, software, and data are stored in a read/write Random Access

Memory (RAM). The memory is a critical part of the stored program control system. It contains the memory stores of all of the basic operating instructions for the system, plus data on the configuration of the particular application being served. Memory utilization is dependent upon what features are programmed into the system and the number of peripheral terminations being served. The memory is split into four segments to facilitate processor address purposes and permit a functional separation of programs.

Unprotected Data Store

(LIDS):

These pages hold the transient or unprotected data that is required during call processing. Included are the timing queues and call registers.

Protected Data Store (PDS) : This protected data store holds the office data blocks that are particular to specific installations.

Program Store (PS): Allocations within the Program Store are as follows:

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System overview 553-3001-I 00

System architecture 17

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Firmware - This portion of the memory is a non-volatile Read Only Memory (ROM) used for storage of all system fiiware. The ROM is programmed during manufacture and the instructions

are permanent and indestructible. It stores the basic rules of operation necessary to initialize the system

and

bring it into a working state. A recovery or “trap sequence” is included in fiiware which is automatically invoked in response to power-on, system reset, or when certain faults are detected.

Overlay - This portion of the memory may be loaded with

various non-resident programs as required during automatic

diagnostics, service order change, traffic measurement, or

maintenance. Software - The remainder of this memory page is reserved for all

of the system software such as the call processing and optional programs. Additional software storage capability is provided by the incremental addition of more memory pages within this category.

Input / Output Addresses - There are no RAM modules utilized for this page. Instead the address range is reserved for Input/Output (I/O) device addresses. These devices include

signaling for peripheral equipment along with magnetic tape and terminal assignments.

Network equipment

Network equipment consists of network circuit cards which perform the

digital switching of voice and data signals, peripheral signalling cards which

perform scanning and signal distribution. , and service circuit cards, such as

tone and digit switches, which provide call progress tones and outpulsing as instructed by the CPU. Network circuits employ Pulse Code Modulation

(PCM) and Time Division Multiplexing (TDM) to perform the switching

function.

Loops and Superloops

Network equipment interfaces with peripheral equipment via digital multiplexed loops. A loop is a bidirectional path between Network equipment (NET) and Peripheral equipment (PE) for voice, data and signalling information. Upon commands from the CE, the network establishes a path, linking a specific input to a specific output.

System overview 553-3001-l 00

18 System architecture

Meridian 1 systems provide two network circuit cards, the QPC414 Network Card which provides 2 loops per card, and the NT8DO4AA

Superloop Network Card which provides 4 loops per card, grouped together in an entity called a Superloop. The Superloop permits all 120 ‘timeslots

provided by the network card to be shared among the peripheral devices

served by the superloop, providing higher traffic capacity and simplified traffic engineering.

The flexibility of the network loop plays an important role in the Meridian 1 architecture. Besides the ability to increase circuit-switched bandwidth on an incremental card basis for cost-effective growth, application may be varied for connectivity of all devices irrespective of how they connect to the system.

The network loop is a key element in the implementation of Computer to PBX Interface (CPI) and Digital Trunk Interface (DTI). CPI provides an

integrated interface for connecting large numbers of host computer ports via

24 channels each supporting up to 19. 2 kbps for asynchronous data or up

to 56 kbps for synchronous data. DTI provides a digital link of 24 channels

each of which may be flexibly allocated for both voice and data

communications. Both CPI and DTI use the North American T-l standard (DS-1 format) and each equipped link is assigned an associated network loop.

value

added services. The network structure allows for the full

Network organization

Network loops are organized into groups. Systems are configured as half, full, or multiple group machines. A half network group machine provides a up to 16 loops, a full group system provides from 17 to 32 loops, while a

multiple group system provides from 33 to 160 loops.

For applications beyond the traffic handling capability of the single network group, additional switching stages are introduced to form a multi-group

arrangement. These connecting paths , provided by the InterGroup Module,

are merely an extension of the originating and terminating network loop

involved in a call. There are eight one way junctors from each group to all

others. Since each path provides thirty connecting channels, a total of 480

connection paths exist from one group to another - 240 in each direction.

Five network groups may be interconnected to constitute a fully configured

digital switching matrix.

System overview 553-3001-l 00

System architecture 19

Network/Peripheral configuration

The allocation of peripheral equipment to the network loop determines the traffic handling capability of the switching network. The lower the number of terminations, the higher the loop traffic capacity. The quantity and type of terminal assignments are allocated to optimize the traffic handling capabilities of the switching network.

A universal PE bus structure permits any mix of PE card types to be located in a PE module. Provisioning of PE cards and their associated density (number of ports) determines the network loop to PE module configuration. Complete modularity permits voice and data modules to be segregated so that the specific traffic patterns of one may be met without impeding the

other.

Enhanced Network Configurations

For peripheral equipment housed in NT8D13 PE modules, network capacity may be allocated in single lcop mode and dual loop mode. In single-loop mode, one peripheral equipment module is connected to one network loop, yielding a maximum concentration of 160 terminations to 30 time slots. In dual loop mode, half of the PE cards in a module use one loop, and the other

half use another loop, yielding two maximum concentrations of 80

terminations to 30 time slots.

System overview 553-3001-100

20 System architecture

Figure 2 Single and dual loop configurations

QPc414

ENET

Circuit

Pack

Network Loop

PE UEMIOR SHELF

PE UEMI OR SHELF

$F[

PE UEMl OR SHELF

Two Network Loops Connected To One PE Shelf Containing Single, Double Or Quad Density PE

Ctrcuit Packs

One Network Loop

Connected To Two

-PE Shelves Containing

Single Or Double Density PE Circuit

Pa&s

System overview 553-3001-l 00

Combined

Single And Dual Loop Connections

To Three PE Shelves Containing Single Or

Double Density PE

Circuit Packs

System architecture 21

Superloop Network Configurations

The Superloop Network Card combines four regular network loops to make

120 timeslots available to PE cards housed in Intelligent Peripheral

Equipment Modules. This increased bandwiath and larger pool of timeslots

increases the network traffic capacity by 25% for each 120 timeslot bundle. The NT8D37 Intelligent PE Module is divided into segments of 4 card slots. These segments are numbered O-3. Segment 0 consists of PE slots O-3,

segment 1 consists of card slots 4-7, segment 2 consists of card slots 8-11,

and segment 3 consists of card slots 12-15.

A Superloop may be assigned from one to eight Intelligent PE segments. A

number of different superloop to segment configurations are possible. The

configuration chosen will depend upon system traffic requirements and the

specific PE cards used. Figures 4 through 9 illustrate different superloop to

segment configurations. Note that the TN to Timeslot concentration figures (figure 3) are nominal, and may vary from segment to segment.

‘-

System overview 553-3001-100

22 System architecture

Figure 3

NT8D37 lntellegent Peripheral Module segmentation

segment 0

Line Cards:

NTBWPAA Digital Line Card 16 to 32 TNs

NT8W3AA

NTBDOSAA Message Waiting Line Card 16 TNs

TN density:

Per segment 16 iu 128 TNs Per IPE module 64 to 512 TNs

Note: Maximum TN density assumes ail slots equipped with

provisioned. Typical mix of line and trunk cards yields a

Analog Line Card 16

segment 1

NT8DMM

nor&al

density of 64 TNs per segment. 256 TNs per

segment2 --

Trunk Cards:

NTBD14AA Universal Trunk Card 8 TNs

NT8DlMA

Diiital Line Cards with 16 voice and 16 data TNs

E&M Trunk Card 4 TNs

Segment 3

IPE

module

System overview 553-3001-l 00

,.‘i‘...

:::.--:., ,\*

1 segment per Superloop

In this configuration, 1 segment is assigned to 1 Superloop (see Figure 4).

In cases where the segment is populated with NT8DO2AA Digital Line

Cards with all 16 voice and all 16 data TNs provisioned, the.1 segment per

superloop configumtion will provide a virtual non-blocking (120 Timeslots

to 128 TNs) environment (see Figure 2) Four NT8DO4AA Superloop Network Cards and one NT8DOlAC Controller-4 Card are used to implement a 1 segment per superloop configuration.

Figure 4 1 segment per Superloop configuration

Segment

segment

I I

System architecture 23

Ssgmem 2 Segment 3

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System overview 553-3001-l 00

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