Pakistan Telecommunication Company Limited
INTERNSHIP REPORT
HUAWEI C&C08
SIEMENS EWSD
ZTE
PRESENTED TO:
DIRECTOR PHONES DIGITAL ITR, PTCL ISLAMABAD
PRESENTED BY:
● RABIA JAMIL
● SALEHA IQBAL
COMSATS Institute Of Information Technology, Islamabad
DEDICATED
To our dear Pakistan which is our identity & which deserves to be returned more
than it gave us.
ACKNOWLEDGEMENT
First of all we would like to thanks to ALMIGHTY ALLAH by the grace &
help of which we have been able to complete this project.
Thank you to the wonderful people at PTCL who continue to provide
support, warm encouragement, patience and guidance.
Thanks to all the people who took the time to voluntarily send encouragements &
suggestions for this project. Your input and help is very much appreciated.
Truly thanks to our dear parents for genuine support & encouragements.
This task is dedicated to the covenant of God with man on earth.
Table Of Contents
Chapter1: EWSD EXCHANGE
 Structural Units Of EWSD Exchange
 DLU (Digital Line Unit)
 LTG (Line Trunk Group)
 SN (Switching Network)
 CP (Coordination Processor)
 Functional Units Of EWSD Exchange
 Control
 Switching
 Signaling
 Access
 Power
Chapter2: HUAWEI PRI EXCHANGE
 Over View & Background
 General Introduction Of C&C08 Switch System
 Overall Structure
 Modular Structure
 Central Module
 Alarm Box
 C&C08 Maintenance System
 Physical Characteristics Of The Switch
 Access Network
 Access Network IBA-I Islamabad (C&C08)
Chapter3: ZTE EXCHANGE
 General Introduction
 ZXJ10 (V10.0) System Description
 System Over View
 Hardware Configuration
 Peripheral Switching Module (PSM)
 Major Functions Of PSM
 Hardware Structure Of PSM
 The Remote Switching Module (RSM)
 Message Switching Module (MSM)
 Central Switching Network Module (SNM)
 Operation & Maintenance Module (OMM)
 Mobile Peripheral Module (MPM) & VLR Module VPM
 Packet Handling Module (PHM)
 Internet Access Module (IAM)
EWSD (Eidal Widal Switch Digital)
EWSD is the digital exchange made by German Company Siemens. This is the very
reliable exchange which is mostly used in Pakistan.
This type of digital exchange is used as local, tandem, transit as well as international gate
way exchange.
The most common switch is used as main exchange. This can operate as PSTN, ISDN
(BRI), PRI, CMMERCIAL Subscriber (Pay phones).
Structural Units of EWSD Switch
EWSD switch can be divided into following parts.
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Digital line unit (DLU).
Line trunk group (LTG).
Switching network (SN).
Coordination processor (CP).
DLU (Digital line unit)
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DLU provides the gateway to the EWSD exchange.
The data of home and commercial subscribers are stored in specific modules in
DLU.
The telephone ring is generated in DLU.
The metering of voltage is done in DLU.
Provides contact with DIU (digital interface unit).
Functions Of DLU
FMTU
Processor
and
Controller
Testing
LCMM
BDCG
RGMG
DLUC
Digital
Line Unit
Interface
Power
DCC-CR
Subscriber
line circuit
(SLC)
DIU
BDB
BDE
SLMACOS
SLMACMRL
SLMAITF
SLMD
Modules of Digital Line Unit
1- Subscriber Line Module (SLM)
SLM modules store the data of all types of subscribers that includes PSTN, ISDN, PRI,
home users and commercial users. In IBA1-A there are two types of SLM modules
 SLMA COS.
 SLMA CMRL.
The SLMA COS module supports 8 subscriber telephone lines and connects them to the
exchange.
The SLMA CMRL module supports 6 commercial lines i.e. public call offices and
connects them to main exchange.
2- Bus Distribution Base(BDB)
The BDB module controls all the buses that are running throughout the DLU. The BDB
modules are present in the first frame and they monitor the sub control units BDE’S that
are control units of the bus in the other frames.
3- Bus Distribution Extension(BDE)
The BDE modules are control units of different shelves of a single rack of the EWSD
exchange. The BDE module is controlled by BDB.
4- Ring Generation and Measuring Module (RGMG)
The RGMG module generates ring and it also acts as metering unit for voltage in the digital
line unit.
5- Digital line Unit Control (DLUC):
The DLUC module is the main control module in the DLU .it monitors all the
functionalities of different modules of the DLU.
6- Bus Distribution Clock Generation (BDCG):
This module generates the clock for bus distribution so that all the buses are
synchronized.
7- DCC:
One DCC module provides the voltage to first eight modules of a shelf and the later
eight modules are supported by an other DCC module at the end of the shelf.
Physical Rack Diagram of DLU (IBA 1-A):
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Line Trunk Group (LTG)
The line/trunk group (LTG) forms the interface between the digital environment of the
node and the digital switching network (SN). The LTGs perform non-central control
functions and thus relieve the coordination processor (CP) of routine work.
Functions of LTG:
Following are the major functions of LTG
 LTG provides direct connection of one exchange with the other exchanges of the
same city or the other cities.
 LTG generates telephone tone.
 LTG provides a gateway to the switching network.
 LTG provides interface between DLU and PCM.
FUNCTIONS OF LTG
4 x DIU’s
Interfacing
SILC-B
SILC-C
CGS
M
Trunk
Sync
&
Switchin
g
Module
DCC-DE
Code
Receiving
Line Trunk
Group
Power
Signaling
CRP
Tone
Generator
Memory
Unit
PMUB
PMUC
PMUD
GSL
Several LTG types are available for optimal implementation of the various line types and
signaling methods. The two main types of LTGs (differing in their functionality) used are:
 LTG-B
● LTG-C
TOG
Physical Rack Diagram:
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LTG-B
The LTGB is used for connecting:
 Up to four digital transmission routes (PDCs) for DLUs at transmission rates of
2048 kbit/s
 Up to four primary rate accesses (Pas) for medium-sized and large ISDN PABXs
(ISDN subscribers with PA) at a transmission rate of 2048 kbit/s.
Main Components of an LTG-B
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Group processor (GP)
Link interface unit between line/trunk group and switching network (LIU)
Group switch (GS)
Speech multiplexer (SPMXA)
Signaling unit (SU)
Line/trunk unit (LTU)
Switching Network (SN)
By virtue of its high data transmission quality, the switching network can switch
connections for various types of service (for example telephony, facsimile, teletext, data
transmission).
This means that switching network is also ready for the Integrated Services Digital
Network (ISDN).
Functions OF Switching Network:
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Duplicated (full redundancy)
Highly-Integrated switching network modules
One space stage module can handle up to 1024 simultaneous calls with full
redundancy
Interfaces of 8,192 Kb/s available within
Highly compact design from space-saving point of view
An exchange of 10,000 subscribers may accommodate the SN in a single rack
Two kinds of connections: Switched & Semi-permanent
Structure:
In large and very large exchanges the capacity stages of the switching network
(SN:504LTG, SN:252LTG and SN:126LTG) include
 One time stage incoming (TSI)
 Three space stages (SS)
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One time stage outgoing (TSO)
Medium-sized and small exchanges (SN:63LTG and SN:15LTG) contain
 One time stage incoming (TSI)
 One space stage (SS)
 One time stage outgoing (TSO)
Physical Rack Diagram:
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Coordination Processor:
The CP performs the following functions in a network node:
 Call processing
 Operation and maintenance
 Safeguarding
The CP consists of the following processors:
 Base Processors
 Call Processors
 Input / Output Control
 Bus for Common Memory
 Common Memory
 Input / Output Processors
Coordination Processor Modules
1. BAP:
The BAPMs and the BAPSs provide the same software functional units.
2. CAP:
The CAPs mainly include software for call processing functions.
3. IOC:
IOCs have only firmware for communication with the call processing, O&M and data
communication peripheries.
4. BCMY:
The bus for common memory (BCMY) connects all processors (BAP, CAP), including
the input/output controls (IOC), with each other and with the common memory (CMY).
5. CMY:
The common memory (CMY) includes, among other things, the common database for
all processors, plus the input and output lists for the IOP. The CMY is duplicated in
order to ensure a high level of availability.
6. IOP:
Different types of input/output processors (IOP) connect the CP113D with other units
in the network node, the external bulk memories, the operation and maintenance
terminal, the operation and maintenance center (OMC, via data
lines)
and
computer centers (also via data lines).
Functionality of CP
BASE
PROCESSOR
COMMON
MEMORY
BUS FOR
COMMON
MEMORY
COORDINATION
PROCESSOR
INPUT/OUTPUT
CONTROL
CALL
PROCESSOR
INPUT/OUTPUT
PROCESSOR
Functional Units of EWSD exchange:
The EWSD system is divided into different functional areas called subsystems coordinated
by a central system. Following are the main functional units of EWSD exchange.
1. Control
2. Switching
3. Signaling
4. Access
5. Power
Control
Control belongs to the area which is responsible for the coordination of the various
subunits. Control consists of the following:
Coordination Processor (CP)
 Message Buffer (MB)
 System Panel (SYP)
 Central Clock Generator (CCG)
Message Buffer
The task of MB is to control the exchange of messages between the following subsystems:
 Coordination Processor (CP) and line/trunk groups (LTG): Commands
and Messages
 CP and switch group controls (SGC) of the switching network: Setting
commands for the SN
 LTGs among one another: Reports
 LTGs and the common channel signaling network control
(CCNC):Orders
Message Buffer Group
The message buffer is divided into functional groups called Message Buffer Groups
according to the expansion concept. One message buffer group consists of one message
buffer unit for Switch Group Control and two message buffer units for LTG.
In the least configuration, at least one message buffer group may exist with at least one
MBUL and one MBUS active where as the other MBUL may be inactive.
In the highest configuration, there are up to 4 message buffer groups with 4 MBUS and 8
MBUL.
Central Clock Generator
In order to switch and transmit digital information, the sequence of operations must be
synchronous throughout the equipment involved.
This requires a clock supply with a high level of reliability, precision and consistency for
all the nodes in the digital network.
This task is fulfilled by the central clock generator (CCG).
Depending upon the accuracy required, the following two modes of operation are possible.
Control System Panel
The purpose of the system panel is to display alarms and advisories of internal and external
supervisory units outside the system) both visually and acoustically.
It is divided into two parts namely the System Panel Control and the System Panel Display
unit.
Switching
By virtue of its high data transmission quality, the switching network can switch
connections for various types of service (for example telephony, facsimile, teletext, data
transmission).
This means that switching network is also ready for the Integrated Services Digital
Network (ISDN).
Signaling
The EWSD digital electronic switching system can control connections to and from other
network nodes using all the common signaling systems.
The signaling functions in a EWSD network-node are handled by the "common channel
signaling network control (CCNC)".
One system that is particularly suitable for stored-program-controlled digital nodes is
signaling system no. 7.
This transports signaling information separately from the user information (voice, data) on
common-channel signaling links.
Advantages
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Higher speed signaling
Very reliable signal transmission
Flexibility to adapt to future requirements
Suitable transmission Medium
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Copper Wires
Optical Fibers
Digital Radio Links
Satellite links
Access
This includes:
 Line / Trunk Group (LTG)
 Digital Line Unit (DLU)
 Digital Announcement System (DAS).
DAS explained:
The digital announcement unit announces recorded messages to the subscriber relating to
different matters such as reason for disconnection or the disability of a non STD phone to
dial an outstation call. The necessary information for such an announcement is provided by
CP and DLU.
HUAWEI PRI EXCHANGE (C & C08)
OVER VIEW & BACKGROUND
PRI stands for “Primary Rate Interface”. The PRI exchange connects the ISPs and the
subscribers of the telephone line. C&C08 is the PRI exchange installed at IBA. It is
manufactured by Chinese company Huawei.
This exchange is installed in the premises of the office of the general manager Islamabad
Telecom Region. It is in the jurisdication of divisional engineer phones IBA-I Islamabad.
Only PRI connections are provided to different ISPs working in Islamabad through this
exchange.
The basic theme of installing a separate exchange for ISPs was to reduce the traffic from
EWSD & ZTE exchanges through which PSTN services are being provided to normal
subscribers in the communication division of IBA-I because these exchanges started being
overloaded due to the increasing use of internet everyday.
Pakistan Telecommunication Company Limited decided to install a separate exchange
for this purpose. Huawei Technologies, China a leading name among the manufacturers
of telecommunication switches all over the world came forward to install this exchange as
a gift to PTCL, strengthening the bridge of Pak-China friendship.
The most popular & widely used switch of Huawei Technologies, C&C08 is installed &
giving extremely remarkable performance in PRI exchange IBA-I Islamabad. Initially
there is a provision of one hundred (100) PRI connections but it is expandable & PTCL is
planning to extend it.
Let us now discuss the important features of C&C08 in detail.
GENERAL INTRODUCTION OF C&C08 SWITCH SYSTEM
THE MEANING OF C&C
 City & Countryside
 Computer & Communication
 China & Communication
PROFILE OF C&C08
Universal frames & racks are used in C&C08 digital SPC switching system. The boundary
dimensions of a rack are “2100×800×550mm, & such a rack can hold six
“620×300×279mm” standard-sized frames with each frame being able to hold 26 plug-inunits (boards).
This kind of modular structure can facilitate the installation & capacity expansion of the
system as well as adding of new devices to introduce new functions.
Different functional boards can be chosen to handle various signaling networks, & through
the adding new functional frames or modules, a wide variety of new functions &
technologies can be introduced to expand the system application area.
OVERALL STRUCTURE
A C&C08 system is composed of a central module & multiple switching modules. The
central module is composed of the administration module/communication module
(AM/CM).
Hardware
It is a state of the art telecom technology which proves the skills of Chinese engineers.
A schematic sketch of C&C08 is given as under.
MODULAR STRUCTURE
BAM:
LIM:
SM:
SPM:
LAN:
PDF:
BAM:
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Back administration module
Line interface module
Switching module
Service processing module
Local area network
Power distribution frame
It is a super computer
It is a powerful administration plat form.
State of the art computer functioning as server.
User through background i.e LAN can implement maintenance, test, billing & other
features.
LIM:
 Mainly it is in the charge of Multiplexing & demultiplexing the services &
signaling data.
 It is connected to SM through a 40.96 Mbps Interface.
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STM-1:Trunk Interface
E-1:Trunk Interface
SM:
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It is the hardcore of C&C08
It has distributed relational data base management.
It handles call processing.
Operation & Maintenance
It has alone switching capacity.
Stand alone single module exchange.
SM & AM/CM are interconnected via fiber optics.
Maximum 128 SMs can be connected to a AM/CM.
It consists of 6 frames
It consists of 1 to 8 racks.
SPM:
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It is in charge of handling various & V5 services.
Equal in functions to SM but with much more powerful capacity.
Working with interfaces of E-1
It is connected with BAM via 10M/100M interface using TCP/IP protocol.
SRM:
 Shared Resource Module
 Provides shared resources of entire system ( DTR,MFC Transceiver, FSK, CONF,
SPD) required by SPM such as:
 Signal tones
 DTMF device
 MFC device
 Conference telephone device
 CID display
AM:

It is comprised of FAM ( Front administration Module) & BAM (Back
administration module)
 BAM interconnects SMs & client server
 FAM performs following functions
 Inter modules call connections
 Real time switching control & management
 Ticket processing
 Traffic statistics
 FAM & BAM are interconnected via 1 to 6 10/100M TCP/IP ports
Ethernet
LAN
BAM
(FAM)
Link
(Super Computer)
CM
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It is the communication module:
It is responsible for Inter-SM speech channels & signaling links
CENTRAL MODULE
 The collection of AM/CM, SPM, SRM is known as Central Module.
 It can contain a maximum of 9 racks.
 AM/CM - CPM, CNET, CCM, STM, LIM, BAM & integrated alarm box
STM:
 It is the synchronization timing system
 Its function is synchronizing the system with higher level networks
CPM:
 It is the central processing module
 Its purpose is storage & processing of local office data & management of boards on
AM/CM
HDLC
CPM
CCM
Other Modules
Link
CCM: Central communication module
 112 incoming high ways
 112 outgoing high ways forming signaling switching network
 transmission rats is 2.048 MBPS
CNET: Central switching network
 Incharge of switching regarding voice & narrow band communication
 It has 64 high speed Optical Fiber Links(HOFL)
 Its capacity is 128 K
MPU: Main processing unit
 It is the brain of SM
 Directly controls the boards of MCF through BUS
 It controls user & trunk circuits via nodes
 It also controls sending of tone & voice by SIG board
 It can control NET board to handle call connection
 It communicates with AM/CM, Operation & maintenance system & Load
 MPU software operates through HDLC synchronous serial port
NOD: This card is responsible for the communication between MPU & User frame &
trunk frame
 There are 11 NOD slots for each SM
 The communication between Main NODE & MPU is through Mail box.
 Mail Node & Sub Nodes exchange messages through serial ports

NODES forward the commands to Sub Nodes that are issued by MPU & reports the
states of Sub Nodes to MPU
SIG: This is Digital signal tone board
 It provides 64 paths of signal tones
BNET-A:As the name indicates this card (module) is used for the switching purposes.
 It forms Intra Module Switching Network
 4K * 4K switching network provides 128 High Ways
 64 are used by own system resources
 64 are freely distributed in users & trunks
CKV: It drives the differential clocks of the functional units i.e ASL & trunks
 CKV is a part of the BNETA board
 Either board alone, BNETA, or CKV can not work normally
ASL: This is Analog subscriber Line card
 This card provides all the telecommunication services to the normal subscribers i.e
analog subscribers or the internet service providers
 It is present in SM
 1 ASL frame has 19 ASL cards
 1 ASL card has 16 subscribers
 1 ASL frame has 304 subscribers
ET-16 Card: This type of cards are present in Line interface module
 Each ET-16 card has 16 E-1s
 Each E-1 has 32 channels
 One PRI ( Primary rate interface) means One E-1
 When it is about normal telephone subscribers we can provide 16 telephone
lines(connections) from one E-1 & 256 from one ET-16 cards, but when it
comes to ISPs one or more PRIs are provided to them, that means one or more E1s.One E-1 or PRI means 32 communication channels similarly two PRIs means 64
channels of communication.
DSL:
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Digital subscriber line card
The subscribers who need digital services are accommodated here
It provides digital services like ISDN(Integrated services digital network)
In case of ASL PRI is provided & in case of DSL, BRIs (Binary rate interface) are
provided
There can be a maximum of 8 users in one DSL card. This means 8 BRIs can be
provided at a time from a single card
Each BRI has 64 communication channels

Currently no BRI is provided to any subscriber from this exchange (switch) in the
territory of IBA-I
PWC: Power card
 Its major function is as secondary power supply
 4 PWC boards can power 2 frames, that means each frame has 2 PWC boards
 Its output is 5 V/ 20A D.C
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ALARM BOX
It alarms a system fault
It is connected to BAM & work stations via serial ports
Presenting audible & visual system
Categorically we can say that alarms are related to four types of systems, these are
namely:
 Power supply system
 Exchange functions
 Self alarms
 Exchange related environment
C&C08 MAINTENANCE SYSTEM
This is the software which is being used for the subscriber administration, fault
maintenance & controlling the operation of this switch. This same software is installed in
the FAM (LAN) & BAM (Super computer).
The version of this maintenance system currently in use is V 6.1.0.This is a very
user-friendly windows based system that allows the administrator to allow a number of
operators to administer the switch & to restrict them from certain operations. Every user
has its own login name & password to achieve the authority of administering the switch.
This software provides the user the ability to test or detect the fault in any part of the switch
as well as a particular user’s line. Also the administrator can add value aided services to
subscriber’s service e.g., CLI, Call waiting, Conference calling etc.
Access Net Work
This net work topology is used to access & control the system being operated at a distance
through optical link by means of an administration terminal. The idea of
Utilising this type of net work in Public switched telephone net work came from the
problems caused by the copper plantation such as maintenance, fault locating & heavy in
cost etc.
To have a better understanding of this net work let us consider an example of such a system
installed & being used in communication division IBA-I of Pakistan Telecommunication
Company Ltd.
ACCESS NET WORK IBA-I ISLAMABAD (C&C08)
About four thousand customers (4000 telephone connections) of PTCL are located in Saudi
Pak Tower, one of the largest business empires in Islamabad. For this purpose eight
thousand copper lines (one pair for each connection) were planed under ground which were
originating from Divisional office of IBA-I & terminating in the premises of Saudi Pak
Tower at a distance of about five to seven kilometers from IBA-I.
It is obvious that copper plantation of eight thousand lines of this much length is
very much expensive & also a tough job to do. The maintenance of this plantation requires
the services of a line staff dedicated particularly for this business estate. In case of line fault
in any of the connections the earth has to be dug out for even kilometers to locate the fault.
Line losses are also of great significance in this respect. Many a time lines become noisy
due to many external & internal factors affecting the signaling which results in distortion &
disturbance in voice & data communication.
As a remedy for this problem ,access net work technique is employed using a well
known & state of the art switch by HUAWEI TECHNOLOGIES, brand name C&C08.This
switch is being used as the accessing tool in the net work.
The telephone connections to Saudi Pak Tower building are provided by the IBAIA exchange, which is a SIEMENS most famous & widely used switch, brand name
EWSD. Since SIEMENS EWSD has CCS7(Common channel signaling) type signaling &
HUAWEI C&C08 employs V5.2 signaling so there is a mechanism in between that
decodes & converts CCS7 to V5.2 mode.
A pair of optical fibre is originated from digital Interface Unit of EWSD
Exchange passing through the digital distribution frame it enters the trunk frame of C&C08
switch. This trunk is placed with another truck in Access Net Work Room in IBA-I. From
other side of the trunk frame the optical fibre pair goes into the AV-5 frame of the second
trunk placed beside it. The signaling was CCS7 up to here. Now from this frame an optical
link originates & terminates in the premises of Saudi Pak Tower. There it enters the module
SBA 155/622 H, from MDF four thousand pairs of copper wire are planted & taken to the
desired locations where the telephone connections are to be provided.
This net work has reduced the length of copper wire as it is used between the MDF
(S.P.T) & desired locations in Saudi Pak Tower. These four thousand connections are being
administrated from IBA-I by means of an administration terminal (PC) which is connected
to the main control frame of the switch C&C08.The administration of the connections
includes fault location & rectification, billing, disconnection & provisioning of different
value aided services e.g., CLI, Call waiting & Code barring for nation wide is international
dialing etc., the employment of this net work has reduced the line staff which was
appointed before & also increased the efficiency of the PSTN services provided by PTCL.
The switch C&C08 is used on testing basis which is a gift from the HUAWEI
technologies China Inc. to the PTCL. The office of the HUAWEI Technologies is also
located in the premises of the Saudi Pak Tower, this switch is working efficiently & has
shown a remarkable performance regarding fault occurrence till date, PTCL is planning to
install this type of net works through out the country to reduce the expenditures &
problems faced due to copper plantation.
A trunk diagram shown below will give a better understanding of the net work
topology.
DIUs
L
T
G
CCS 7
SIGNALING
D
F
F
IBA-IA
PCM HALL
EXCHANGE
TRUNK
FRAME
EMPTY
EMPTY
EMPTY
CLOCK
FRAME
MAIN
CONTROL
FRAME
EMPTY
AV-5 FRAME
MCF
SBS
155/622
H
BAM
RAM
ACCESS NET WORK ROOM
V
5.2
S
I
G
N
M
OPTICA
-L
AIR
CONDITIONING
UNIT
SBS
155/622
H
D
LINK
SUBSCRIBER
LINE
CARD
F
SUBSCRIBER
LINE
CARD
SAUDI PAK TOWER
F
ZTE EXCHANGE
ZTE is a Chinese telecommunication company that was founded in 1985.Initially it had its
network limited in different cities of China later on ZTE extended its network to different
countries of Asia and Africa.
Unlike EWSD, ZTE is modular based exchange and in each module we have its own
control system, switching network and signaling network.
At IBA exchange a ZTE exchange named ZXJ10 is installed. It has capability of supporting
10000 lines. A detailed diagram of ZTE’s module is shown in the next page.
The main advantage of having a ZTE exchange is its low cost. The ZTE exchange costs
almost eight times less than that of Siemens, Ericsson or Alcatel. That is the reason why
ZTE is becoming so popular in the developing and poor countries of Asia and Africa.
The disadvantage of ZTE exchange is that it is not as reliable as EWSD, Ericsson, Alcatel
or even Huawei. ZTE exchange suffers from more errors than other exchanges.
ZTE
1
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ALAR
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ZXJ10 MODULE
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+5
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Master
Standby
Offline
Alarm
Power
ALAR
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Switch
Reset
On/off
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ALAR
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Standby
Offline
Alarm
Power
Switch
Reset
On/off
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ZXJ10 (V10.0) SYSTEM DESCRIPTION
SYSTEM OVERVIEW
The ZXJ10(V10.0) digital SPC switching system employs an open architecture with full
distribution between modules, hierarchical control, inside modules & centralized
administration. It is based on general purpose computers & is supported by local area
network. It employs the client/server mode as its control structure, so that the system is
flexible in networking & powerful in call handling with high reliability & good
compatibility & expandability.
HARDWARE CONFIGURATION
Aided by a full contribution control system, ZXJ10 can hold one to several dozens of
modules in accordance with the exchange capacity. Besides, in terms of services demands
& geographical locations, this system can be expanded with different modules. Except the
OMM module, each module consists of a pair of active/standby MPs ( Master processor ),
several SPs ( Slave processor ) & some single boards, PSM SNM, MSM, RSM, RLM are
the basic modules of the ZXJ10 foreground network, while OMM makes up the
background network.
PHM
PSM
RSM
IAM
PSM
PSM
RLM
MSM
SNM
RSM
RLM
PSM
RLM
OMM
MPM
VPM
Figure: System structure diagram
OMM: Operation & Maintenance Module
RLM: Remote Line Module
SNM: Switching Network Module
VPM: Visitor Peripheral Module
IAM: Internet Access Module
PSM: Peripheral Switching Module
RSM: Remote Switching Module
MPM: Mobile Peripheral Module
MSM: Message Switching Module
PHM: Packet Handling Module
In the whole ZXJ10 system, all the important equipment is in active/standby mode,
including MP, T net, NETD, COMM, FBI, clock equipment & subscriber unit processors,
etc.
PERIPHERAL SWITCHING MODULE (PSM)
Major functions of PSM:
 In a single module office, it performs the PSTN, ISDN subscriber access & call
handling
 In a multi-module office, it is connected into the central modules one of the
module offices


As the mobile switching system ( MSC ) , it is connected into the central
exchange
As the service switching point ( SSP ) of IN, it is connected into the SCP
Hardware Structure of PSM
The core of the TS switching network pf PSM module is of an active/standby non-blocking
switching network of 8K*8K or 32K*32K, the peripheral interface units & the signaling
units. The internal message paths are established through the intramodule communication
boards (COMM) & the monitoring boards (MONI).The clock employs the loose-coupling
method with its possible maximum accuracy of Stratum 2 & degree A. It can provide builtin Bits systems too.
The full system configuration is of 12480L ( 12480 subscriber lines) + 26700DT ( 26700
trunks) . In every group of 960 subscribers, it interchanges with 240 trunks. Each module
holds 48 NO. 7 links or 24 V5.2 interfaces.
Digital trunk unit
8 Mb/s
8 Mb/s
SNM
FBI
Subscriber unit
SWITCHING UNIT
SIGNALING UNIT
8K * 8K
MFC
DTMF
2 Mb/s
TONE
2 Mb/s
V5.2
NO. 7
COMM
COMM
Control unit
MP0
MP1
2
Figure: PSM structure diagram
PSM employs multiprocessor hierarchical control mode, consisting of the following basic
units.








Control unit: MP, COMM, & MONI, Namely, a single COMM board can process
32 64Kb/s HDLC, with 8K-byte & dual-port RAM. It can serve as MP-PP, MP-MP
COMM, no.7 signaling boards, V5.2 C channel board & 30b + D D channel board.
Moreover, it can monitor the power supply, synchronization unit, & FBI ( fiber
interface ), for instance, the MONI & the PEPD( peripheral environment parameter
detection ) boards
Switching unit: 8K DSN ( digital switching network ) & some DSNIs
Synchronization unit: clock reference card CKI ( if the bits interface required ),
synchronous oscillator SYCK
Peripheral interface unit: DTI, FBI, as well as subscribers & analog trunk boards
Signaling unit: ASIG ( analog signaling board ), TONE, MFC, DTMF, & CID
( caller identification ) board
Subscriber unit: in every 960 subscribers lines, there are 40 ASLCs ( or DSLC ),
each containing 24 analog subscriber lines ( or 12 digital subscriber lines for each
DSLC ). Each unit is equipped with 4 analog subscriber test boards MTT ( or digital
subscriber test boards DMTT ). ASLC & DSLC boards can be inter-inserted, so can
the MTT/DMTT. All the single boards have processors. The subscriber unit is
monitored by two active/standby SPs
Analog trunk unit: the analog trunk unit is controlled by two active/standby SPs
with 22 trunk boards, including the single frequency trunk ( SFT ), the loop trunk (
TRT ), the A/B wire trunk ( ABT ), & the magnetic trunk ( MT )
THE REMOTE SWITCHING MODULE ( RSM )
The internal structure of RSM module is exactly the same as that of PSM except more TSs
from PSM to the central network & their fixed no. is of 2040. However the no. of TSs from
RSM to the central network is comparatively smaller & can be increased at the rate of
every 32 TSs, flexible as well as adjustable.
MESSAGE SWITCHING MODULE ( MSM )
SNM usually employs 4*8K planes, with the maximum expansion capability of 8 * 8K. Its
switching TSs amount to 64K, applicable to various sorts of markets. The HWs from RSM,
PHM are averagely distributed to 8 planes. Considerably the configuration flexibility of
RSM , the PCM links from RSM can be connected to the multi-plane via the switching of a
single T net. Since the connection of each plane can be controlled through a pair of MPs &
two COMM boards with the 256 Kb/s HDLC link, that pair of MPs in SNM can also be
connected with NT server of OMM via Ethernet so as to serve the message transmission
between OMM & other related modules.
MSM
MP0
MP1
COMM
COMM
...........
COMM
COMM
n * 64Kb/s
COMM
COMM
PSM+
MP0
MP1
PSM+
Figure: MSM structure diagram
PHM
CENTRAL SWITCHING NETWORK MODULE ( SNM )
The major function of SNM is to perform not only the TS switching between PSM & PSM
but also the B-channel connection between PSM & PHM.
Multi-Plane
S net
S T
PSM
( Tn )
PSM
( Tn )
S T
PSM
( Tn )
.
.
.
.
.
PSM
( Tn )
PSM
( Tn )
S T
PSM
( Tn )
Figure: Multi-module Test connection diagram
After the semi-permanent connection, SNM will transmit the TSs from the multi-module to
MSM to support the n * 64kb/s switching. It can be applied to the ISDN H0 channel
transmission, making the alternation of the communication bandwidth n * 64kb/s ( n≤32 )
become possible. It can also provide the background with the information channel.
Built-in
fiber
E3
E1
32 *
8Mb/s
Single T net
8K * 8K
RSM
RSM
32 *
8Mb/s
16 * 8Mb/s
PSM
Builtin
fiber
Single T net
MSM
.
.
8K * 8K
COMM
16 * 8Mb/s
Builtin
fiber
COMM
512 Kb/s
512 Kb/s
2 Mb/s
HDLC
COMM
SNM
MP0
s
SingleTn
et8K*8K
COMM
MP1
OMM
Figure: SNM structure diagram
LAN
PSM
SingleTn
et8K*8K
SNM usually employs 4 * 8K planes,with the maximum expansion capability of 8 * 8K
planes. Its switching TSs amount to 64K, applicable to various sorts of markets. The HWs
from RSM, PHM are averagely distributed to 8 planes. Considering the configuration
flexibility of RSM, the PCM links from RSM can be connected with the multi-plane via the
switching of a single T net. Since the connection of each plane can be controlled through a
pair of MPs & two COMM boards with the 256Kb/s link, that pair of MPs in SNM can also
be connected with NT server of OMM via Ethernet so as to serve the ,message
transmission between OMM & other relevant modules.
THE OPERATION & MAINTENANCE MODULE ( OMM )
According the size of modules, SNM can be such types as of 32K, 64K, 128K, 256K, of
which 13K network can be employed to connect with 13 PSMs & 35 RSMs.
The ZXJ10 SPC exchange follows the centralized maintenance management mode.
Its maintenance management network has applied not only the client/server structure which
is based on the TCP/IP protocol, but also the WINDOWSNT4.0 operation system. Its
contents contain such things as data, statistical traffic, billing, system measurement, system
alarm, etc, which are substantial for the management & the maintenance of the exchange.
The handling of the software & the data of the whole system is executed in OMM. Then
SNM transmits the results to each peripheral module, & can be under remote operation as
well as maintenance management.
NT Server
MP
..............
NT
client
NT client
router
DDN
PSTN/PSPDN
NT
client
NT
client
NT
client
Figure: OMM connection diagram
The main processor of MSM ( or other PSM modules ) can be connected into Ethernet via
the standard TCP/IP protocol. As a result, the message interworking between OMM & the
foreground processor is available.
MOBILE PERIPHERAL MODULE ( MPM ) & VLR MODULE VPM
MPM & VPM are developed on the advanced ZXJ10 ( V10.0 ) platform by adding mobile
switching modules MSC & VLR modules, forming the core of the ZXG10 mobile
switching network.
The major function pf MPM is to realize the relevant functions of MSC, that is,
providing the voice trunk, the signaling link to BSS, the tone trunk to PSTN, providing the
link interface to PLMN, at the same time, supporting the message interaction among the
VPMs. In addition , MPM is similar to pure wired trunk module. Within 8KTSs ( eg.
2KTSs to SNM, 2KTSs to BSS ), 4K TSs are for the incoming & outgoing office trunks,
supporting approximately 20 thousand mobile subscribers.
Except the absence of the ASIGF board, the rest of the VPM structure is the same as
that of MPM, & their functions are generally the same. Unlike MPM module , the single T
network of VPM module does not control the connection of the speech channels. Instead it
only performs the connection of the internal control, & the communication signaling, VPM
mainly carries out the functions related to VLR, providing the actual storage &
management in such temporary resources as TMSI, MSRN etc. It also controls the
communication with other network entities eg, VLR, HLR, VPM itself can manage NO.7
signaling handling.
Charging
center
NMC
SNM
X.25
MSM
TCP/IP
OMC-S
PSM
MPM
VPM
TCP /IP
NO. 7 SIGNALING
NETWORK
HLR/AUC
BSS
BSC
OMC-R
TCP/IP
BTS D1800
BSS: base subsystem
MSM: message switching module
MPM: mobile peripheral module
PSM: peripheral switching module (cable)
AUC: authorization center
BTS G900
MSC: mobile switching center
SNM: switching network module
VPM: visitor peripheral module
HLR: homing location register
Figure: ZXG10 mobile communication system structure diagram
PSTN
ISDN
PSPDN
PLMN
PACKET HANDLING MODULE (PHM)
With PSM as its platform, the physical architecture of PHM employs X.25 protocol to
support two call types, namely Case A & Case B.
Case A: B channel packet data are handled by COMM & MP in PHM.
Case B: The switching network transmits B channel packet data to AU (access unit) at
PSPDN side for handling.
INTERNET ACCESS MODULE (IAM)
IAM is developed on the ZXJ10 platform, consisting of the call signaling handling module,
the MODEMPOOL module & the protocol handling module with the purpose of increasing
relevant IP services for ZXJ10. The present services focus on the internet access, IP
telephone/fax: & the provision of remote network access for the subscribers. Via the
common lines, ISDN lines & other private lines, the remote subscribers can get access to
the networks. Furthermore, IAM also provides such services as network subscriber account
management, subscriber authorization & access authorization control, ensuring the
subscribers network access validity. The access capability can be of n*30 lines. The
extension capability can be smoothly achieved by over 20,000 lines
ROUTER
E1/DDN
Internet FBI
ZXJ10
PSTN
IAM
PRI/FR
WWW
SERVER
DNS
SERVER
M
OAM
AAA
SERVER
PC terminal
Figure: Internet access diagram
Telecommunication operators can add internet services effectively & smoothly. This
plays the part of the “data bypass” objectively & consequently reduces the pressure
caused by internet on modern telecommunication networks.
Additionally IAM can be employed to establish not only the large capacity internet
access point so as to make construction of the service groups very flexible, but also the
enterprises INTRANET. Or it can build the VPN network for clients. Meanwhile as the
IP telephone/fax network gateway. IAM can provide internet telephone/fax services for
the end-users, for eg. IPPHONE, IPFAX, internet incoming/outgoing call, analog access
& postal box services.
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