exchange
Swtiching
network
contains
SPC switching
signalling

Interprete and describe the basic principles and functions of exchange.

Recognize switching network and the term "concentrator",
"distributor", "EXPANDER", and "multiplex“.

Draw and label a block diagram of SPC switching.

Identify and describe the signaling principles.
i.
the type of signaling.
Ii.
the type of signal in the signaling between exchanges with
customers.
Iii.
the type of signaling between the exchanges with the exchange.
Tele comes from the Greek word that is long distance,
while Foni is defined as sound or speech.
Telephony communication means the transmission of speech
at long range, where in the wave transmitter
voice changed to the form of electrical signals and then
the signal is converted back to wave
voice.
Frequency bandwidth used for telephony services is
300 - 3400 Hz frequency which is a human voice.
Therefore, all telephony equipment and line connections between the
devices must be able to communicate in the bandwidth.



Is a center where all the phone lines can be connected to enable
communication speech is achieved.
The equipment in exchange functions as a switch for easy connection
process.
Now, most of the exchanges is the type GSC (Group Swicthing Centre)
PPU
PPZ
PPZ
PPK
PPT
P
PPK
PPT
P
P
PPT
P
P
PPK
PPT
P
P
PPT
PPT
P
PPU - Main Switching Centre (MSC)
PPK – Switching Centre Areas
P – Customers
P
PPK
P
P
PPT
P
P
PPT
P
P
P
PPZ - Switching Centre Zone (SCZ)
PPT – Local Switching Center
- two wire cable
3 types of
exchange
Local
exchange
Tandem
Exchange
Available in a
same area
Connecting two or more local
exchanges and its main
features is not connected to
the customer.
International
exchange
Exchanges and tandem
exchanges connecting to
the nation
Record the customer’s meter reading
(time, no.telefon called)
Overseeing the process between the
client and exchange switching
Function of
exchange
Record customer demand
- Provides no. telephone, cut meter for
temporary condition
Provide supervisory signals (dial tone,
ringing, busy tone interference)
Control the quality of conversations and
recorded service quality of exchanges .
Switching Network.
Some of the required switching are:Concentrator ( Penumpu)
Distribution ( Pengagih )
Expander
Multipleks ( Multiplexer )
The combination of these networks can create complete Public Switching
Telephone Network (PSTN).

Permanent circuit connections made ​in this network.

Concentrator unit is controlled by the local switching exchange directly.
distributors
Customers
Concentrator (Penumpu)
The concept of traffic in the PSTN network
►The distributor (distributor) is a device between the concentrator
(concentrator) and expander. This device is connect thousands of
users in the PSTN network in stages.
► Where, about 1000 local line will enter the off-line and only produce
100 output. Next, each distributor can handle 100 online from the
concentrator.
► Then, the line from the distributor, will enter the EXPANDER.
Output
channel
input channels
Local line 1
distributors
Expander
concentrator
Local line
Local line 1
Local line
1000
1000
Switching network of PSTN
 This returns the number of units of the original line into the
concentrator.
 From the distributor, all the 100 line will enter the EXPANDER and
reissue of 1000 online consumers in the destination separately.
 EXPANDER and off the switching process depends on number of
lines that is activated simultaneously.
►This device is a tool that can reduce the number of cabling to be used in a
process of signal transmission and receiving information.
►This may be achieved by combining several input signals and produces an
output only.
►This combination technique known as multiplexing (multiplexing).
♣ Time Division Multiplexing (TDM)
♣ Frequency Division Multiplexing (FDM).
►Demultiplexing - separating the information to the original signal.
Signal Information 1
Signal Information 1
Signal Information 2
Signal Information 10
DEMUX
MUX
Signal Information 2
Signal Information 10
It is a process of connecting customers from one location to
another through the exchange as the medium of
communication.
Switching functions:
►provide services in facilities known customers.
►when more sophisticated switching system it serves to
provide additional facilities that enable communication
network to provide better service to consumers, and
overseeing the operations and maintenance.

 The main process through the development of telephone calls made ​through a
tone switching step of dialed digits.
The problem of switching step by step:
►Power : requires a lot of power to move the switch for call processing
component.
►Space : The components of the main switch is made from brass,
copper, and magnetic pressure is very heavy and require steel
in the floor where they are fitted.
►Maintenance: a lot of moving parts in a switch requires cleaning dirt and
oil to facilitate the communication is made in the switch.
►Noise: communication through physical path
be adjusted via the switch for call processing.
► Crossbar switching is an improvement from switching the
step-by-step (switching strowger)
► Switching process performed by the relay (pet clothing).
► Consists of vertical and horizontal line.
► Require connection to a combination of two lines.
► This system has a horizontal switch used to select vertical
switch. Horizontal switch function to hold the vertical
switch.
► Other names called switching
matrix.

Merupakan kaedah pensuisan ibusawat telefoni

Ia menggunakan kawalan komputer untuk memproses
panggilan daripada pengguna secara automatik.

Operasi komputer berpandukan aturcara yang telah
ditetapkan.

Sistem dalam bentuk modular iaitu terdiri daripada subsistem

Sistem menggunakan ‘common channel signalling’ (CCS)

Sistem menggunakan ‘time switch’




memory
♣ Keep status of activities of users in software form.
Director of the control (control director)
♣ Programs that control and direct the entire system.
File
♣ Store information of user charges.
♣ Provide special schedules for special services or other
services.
DTMF (decodic)
- Decoding signals produced during the process of dialing




Scanner
♣ Track the status of algae line telephone and
cellular signaling.
Drivers
♣ Connect and disconnect the circuit.
♣ Provide access to the dial tone signal and the
signal.
CPU (central processing unit)
♣ Control and programmed to execute the
program.
Tone generator
♣ Generate a notification signal or a call sign.
1.
2.
3.
4.
5.
6.
7.
A caller picked up the telephone handle, A-line caller is activated
and can be detected by the scanner.
CPU will detect and obtain location information, time and so
when the caller A pick up the phone handle.
Information send to memory for storage.
Thereafter, the CPU will connect the caller A with switching path
'X' through the drive.
Dial tone is sent to the caller A from dial tone generator.
A caller entered digits dialed numbers, a dial tone generated by
the DTMF stopped.
CPU identifying type of call and destination of the call.
8.
Drivers will drive the switching devices 'X' to provide access to the for
caller A with caller B.
9.
CPU provides instruction on tone generator to send ringing tone for
caller B and caller A.
10.
Once the handle of caller B is lifted up, the scanner will detect the
phone picked up and sent to the CPU.
11.
After that, the CPU directs tone generator to stop ringing and start
recording the time and location of the call.
12.
After the conversation ended, whether the caller A or B put handle,
the scanner will detect the emission signal and sent to the CPU.
13.
CPU will provide the bill (payment) and the records are stored in
files.
o
o
o
o
o
Maintenance and monitoring is easy because the method
of exchange operations may be varied by changing the
stored program control at any time.
Signaling from the exchange can be handled easily and
effectively.
Increase in line do not need additional signaling device.
Low maintenance costs.
The process is much faster than manual methods.




Minor damage can lead the exchange operations to
stop.
Ensure that employees trained on new techniques
and methods of handling.
Maintenance of over-reliance on suppliers.
Service requires additional building equipment
such as air-conditioned room and the program.
 Signaling
is defined as a transfer or change of
address or information between different parts
found in a telecommunications system.
 Division involved in the signaling:
►Callers to the exchange
►Exchange with an exchange
►Exchanges with the so-called

Among the callers to exchange
Signal Type
Definition
grab signal(seizure)
Signal when the handle lifted
(off-hook)
Signal ‘clear forward’
Signal when the handle are
placed(on-hook)
Signal ‘address’
Dialing pulses to exchanges

Among the exchange to the caller
Signal Type
ringing signal

Definition
Signal indicates an incoming call
Among recipient to the exchange
Signal Type
Maksud
answer signal
When the recipient pick up the
handle (off-hook)
Signal ‘clear back’
When the recipient put the handle
(on-hook)

The signal from the exchange to the caller or the
receiver(standard service tones)
Jenis nada
Maksud
Dial tone
The resulting tone on the caller after caller lift
the handle. Prolonged sound tone. (example:
tuuuuuuuu ....)
Busy tone
Tone to be received by the caller when the
number dialed is in use. (example: tuut, tuut,
tuut ....)
Tone no number
A voice message will be generated when the
dialed number not in service.
Ringtones
Tone is received by the caller when a call is
succesfully connect. (example: tuut tut, tut tuut,
tut tuut .....)
Channel Associated Signaling,(CAS)
Common Channel Signaling (CCS)
Voice signals and control signals are sent on the
same channel or circuit
Voice signals and control signals are sent through
different channels
Controlled by digital or non digital exchanges
Controlled by computer
Signaling speed is low
Signaling speed is faster
Exchange A
Exchange B
Exchange C
traffic circuit
traffic circuit
Signaling line
Transmitter or Receiver Signaling
Transmitter or Receiver Signaling
Exchange D