Transcript signalling
Swtiching network exchange 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.
Ii.
the type of signaling.
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 PPK PPK PPK PPT PPT PPT PPT PPT PPT PPT PPT P P P P P P P P
PPU PPK – Main Switching Centre (MSC) Switching Centre Areas P – Customers
P P P P P P P P
PPZ PPT – Switching Centre Zone (SCZ) Local Switching Center - two wire cable
Local exchange
Available in a same area
3 types of exchange Tandem Exchange International exchange
Connecting two or more local exchanges and its main features is not connected to the customer.
Exchanges and tandem exchanges connecting to the nation
Function of exchange Record the customer’s meter reading (time, no.telefon called) Overseeing the process between the client and exchange switching 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.
input channels
Local line 1 Output channel Local line 1
distributors
Local line 1000 Switching network of PSTN Local line 1000
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 2 Signal Information 10 Signal Information 1 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
grab signal (seizure) Signal ‘clear forward’ Signal ‘address’
Definition
Signal when the handle lifted (
off-hook
) Signal when the handle are placed (
on-hook
) Dialing pulses to exchanges
Among the exchange to the caller ringing signal
Signal Type Definition
Signal indicates an incoming call Among recipient to the exchange
Signal Type
answer signal Signal ‘clear back’
Maksud
When the recipient pick up the handle (
off-hook
) When the recipient put the handle (
on-hook
)
The signal from the exchange to the caller or the receiver(standard service tones)
Jenis nada
Dial tone Busy tone Tone no number Ringtones
Maksud
The resulting tone on the caller after caller lift the handle. Prolonged sound tone. (example: tuuuuuuuu ....) Tone to be received by the caller when the number dialed is in use. (example: tuut, tuut, tuut ....) A voice message will be generated when the dialed number not in service.
Tone is received by the caller when a call is succesfully connect. (example: tuut tut, tut tuut, tut tuut .....)
Channel Associated Signaling,(CAS)
Voice signals and control signals are sent on the same channel or circuit Controlled by digital or non digital exchanges Signaling speed is low Exchange A traffic circuit Exchange B
Common Channel Signaling (CCS)
Voice signals and control signals are sent through different channels Controlled by computer Signaling speed is faster Exchange C traffic circuit Exchange D Transmitter or Receiver Signaling Signaling line Transmitter or Receiver Signaling