9. 9. Private Private Automatic Automatic

Telephone Based Telephone Based Exchange (PABX)Exchange (PABX)

SystemSpecification

Connection system

Maintenance and Failure Maintenance and Failure DetectionDetection

Communication TechnologyCommunication Technology

Process of delivering information from Process of delivering information from one destination to another destination one destination to another destination by using code and storan system.by using code and storan system.

There is 4 category of communication :There is 4 category of communication :

1. Audio freq - In range of 10Hz to 1. Audio freq - In range of 10Hz to 20kHz20kHz

2. Visual – visible material2. Visual – visible material

3. Graphic – producing information in 3. Graphic – producing information in picture formpicture form

4. Electronic – base on effect of electron 4. Electronic – base on effect of electron flow flow

Private Automatic Branch/Telephone Exchange Private Automatic Branch/Telephone Exchange (PABX)(PABX)

There is 2 types of telephone swithing board :There is 2 types of telephone swithing board : 1. PMBX 2. PABX1. PMBX 2. PABX1. 1. PMBXPMBX Originally an organization's manual switchboard Originally an organization's manual switchboard

(operated by a person plugging cables into sockets) was (operated by a person plugging cables into sockets) was known as a PMBX (Private Manual Branch Exchange).known as a PMBX (Private Manual Branch Exchange).

Based from original system PMBX (Private Manual Based from original system PMBX (Private Manual Branch Exchange) – where the contacted no. is Branch Exchange) – where the contacted no. is connected manually by the operator.connected manually by the operator.

2. 2. PABXPABX PABX is an electronic switching systems that replace the PABX is an electronic switching systems that replace the

manual & electromechanical switching system. manual & electromechanical switching system. PABX system able to conduct call @ call distribution PABX system able to conduct call @ call distribution

automatically with operator @ in direct (w/out operator) automatically with operator @ in direct (w/out operator) if the extension no. available.if the extension no. available.

In addition to telephone sets, fax machines, modems In addition to telephone sets, fax machines, modems and many other communication devices can be and many other communication devices can be connected to a PBX as well (although the PBX may connected to a PBX as well (although the PBX may degrade line quality for modems). All such devices are degrade line quality for modems). All such devices are generally referred to as extensions.generally referred to as extensions.

• A telephone operator manually connected calls with patch cables at a telephone switchboard. Computers make most connections now.

PABX FunctionsPABX Functions

Basically, PABX performs three main duties:Basically, PABX performs three main duties: 1. Establishing connections (circuits) between 1. Establishing connections (circuits) between

the telephone sets of two users. Main switching the telephone sets of two users. Main switching controller that connect & disconnect telephone controller that connect & disconnect telephone connection in a department or office.connection in a department or office.

(i.e. mapping a dialed number to a physical (i.e. mapping a dialed number to a physical phone, ensuring the phone isn't already busy) phone, ensuring the phone isn't already busy)

2. Maintaining such connections as long as the 2. Maintaining such connections as long as the users require them. (i.e. channeling voice users require them. (i.e. channeling voice signals between the users) signals between the users)

3. Providing information for accounting purposes 3. Providing information for accounting purposes (i.e. metering calls) (i.e. metering calls)

In addition to these basic functions, PABXs offer In addition to these basic functions, PABXs offer many other capabilities, depend to the many other capabilities, depend to the manufacturers providing different features : - manufacturers providing different features : -

- Auto Attendant - Speed dialling - Voice mail- Auto Attendant - Speed dialling - Voice mail - Call transfer - Music on hold - Call - Call transfer - Music on hold - Call

waiting waiting - Call forwarding on busy - Conference call- Call forwarding on busy - Conference call

A.A. Specification for PABX designSpecification for PABX design Should follow spec as below :-Should follow spec as below :-1.1. Min. control panel with capability to be Min. control panel with capability to be

connected to PABX/ normal telephone, direct connected to PABX/ normal telephone, direct call (emergency call) w/out operator & call (emergency call) w/out operator & connection to PA system. connection to PA system.

2.2. Digitally design.Digitally design.3.3. Easy to handle modification in user data base Easy to handle modification in user data base

( using software application) with no ( using software application) with no intterruption to other services.intterruption to other services.

4.4. Able to conduct internal call or feed the Able to conduct internal call or feed the connection outside to the public telephone connection outside to the public telephone network @ to the other PABX network.network @ to the other PABX network.

5.5. Power supply – DC (48V) @ AC supply.Power supply – DC (48V) @ AC supply.6.6. Able to conduct manually (operator) or Able to conduct manually (operator) or

automatically.automatically.7.7. Attached with port for connection to ISDN PRI Attached with port for connection to ISDN PRI

(Primary Rate Interface) network. (Primary Rate Interface) network. 8.8. Power supply to customer telephone should Power supply to customer telephone should

supply by the PABX system.supply by the PABX system.

PABX connection system in private area

PABX

Operator

Computer

Telephone

Fax

Rangkaian

PSTN/ISDN

ISDN PRI Line

PABX system connected to the normal telephone PABX system connected to the normal telephone network (PSTN-Public Switch Telephone Network) network (PSTN-Public Switch Telephone Network) pass through the ISDN PRI (Integrated Services pass through the ISDN PRI (Integrated Services Digital Network – Primary Rate Interface)Digital Network – Primary Rate Interface)

User can make internal call without passing User can make internal call without passing through the operator by dialling the last 3 @ 4 no. through the operator by dialling the last 3 @ 4 no. depand to the setting made in the system.depand to the setting made in the system.

Calls on a key system are made by selecting a Calls on a key system are made by selecting a specific outgoing line and dialing the external specific outgoing line and dialing the external number; calls on a PBX are made by dialing 9 (or 0 number; calls on a PBX are made by dialing 9 (or 0 in some systems) followed by the external number; in some systems) followed by the external number; an outgoing trunk line is automatically selected an outgoing trunk line is automatically selected upon which to complete the call. upon which to complete the call.

External call (in/out to private area) will be External call (in/out to private area) will be controlled by operator.controlled by operator.

ISDN PRI that is used for connection between ISDN PRI that is used for connection between PABX to PSTN have a capacity 2.014Mbps that PABX to PSTN have a capacity 2.014Mbps that have 30 channel & capable to conduct 30 have 30 channel & capable to conduct 30 traffic/call even for telephone, fax or dial up traffic/call even for telephone, fax or dial up internet in the same time.internet in the same time.

The no. of PABX user not only 30 user even The no. of PABX user not only 30 user even the external outline can conduct max. 30 the external outline can conduct max. 30 traffic in a time. traffic in a time.

If in one time the user exceed max 30 user, If in one time the user exceed max 30 user, the 31the 31stst user will have to wait until the user will have to wait until the active user disconnect the line.active user disconnect the line.

However, there is no limit for internal call. However, there is no limit for internal call. It’s depend to the capability of the PABX It’s depend to the capability of the PABX system itself.system itself.

Nowdays, the existing public telephone Nowdays, the existing public telephone network in Malaysia is supply by TM and network in Malaysia is supply by TM and Maxis. Maxis.

PABX

Rangkaian

PSTN

Pejabat Utama

Pejabat Cawangan 3

Pejabat Cawangan 1

Pejabat Cawangan 2

PABX connection system for private / branch network

PABX system also can be use for connection PABX system also can be use for connection between the headquarters office and the branch between the headquarters office and the branch office by using the ISDN line .office by using the ISDN line .

The branch office user can communicate with their The branch office user can communicate with their collegue by dialling the last 3 @ 4 no. only.collegue by dialling the last 3 @ 4 no. only.

In addition, a limited number of outside lines In addition, a limited number of outside lines (called trunk lines) are usually available for making (called trunk lines) are usually available for making and receiving calls external to the site (i.e. to the and receiving calls external to the site (i.e. to the public telephone network). public telephone network).

Companies with multiple sites can connect their Companies with multiple sites can connect their PBXs together with trunk lines. PBX services can PBXs together with trunk lines. PBX services can also be provided by equipment located off site at a also be provided by equipment located off site at a central provider, delivering services over the public central provider, delivering services over the public telephone network. This is known as a hosted PBX. telephone network. This is known as a hosted PBX. For example, most local phone companies offer a For example, most local phone companies offer a Centrax service in which each extension has a trunk Centrax service in which each extension has a trunk line connected to the telephone company's Central line connected to the telephone company's Central Office. Office.

Normally, the private/ branch network applied by Normally, the private/ branch network applied by the giant company.the giant company.

ISDNISDN a circuit-switched telephone network system a circuit-switched telephone network system

(computerized) designed to allow digital (computerized) designed to allow digital transmission of voice & data over ordinary transmission of voice & data over ordinary telephone copper wires, resulting in better telephone copper wires, resulting in better quality & higher speeds than that available in quality & higher speeds than that available in PSTN system. ISDN provides simultaneous PSTN system. ISDN provides simultaneous voice, video, and text transmission between voice, video, and text transmission between individual desktop videoconferencing systems individual desktop videoconferencing systems and group (room) videoconferencing systems. and group (room) videoconferencing systems.

PSTNPSTN The public switched telephone network The public switched telephone network

(PSTN) is the network of the world's public (PSTN) is the network of the world's public circuit-switched telephone networks, in much circuit-switched telephone networks, in much the same way that the internet is the network the same way that the internet is the network of the world's public IP-based packet switched of the world's public IP-based packet switched networks. networks.

Interface standardsInterface standards

Interfaces for connecting extensions to a PABXInterfaces for connecting extensions to a PABX include:include:

- - POTS (Plain Old Telephone System)POTS (Plain Old Telephone System) - the common two- - the common two-wire interface used in most homes. This is cheap and wire interface used in most homes. This is cheap and effective, and allows almost any standard phone to be used effective, and allows almost any standard phone to be used as an extension. as an extension.

- - proprietaryproprietary - the manufacturer has defined a protocol. One - the manufacturer has defined a protocol. One

can only connect the manufacturer's sets to their PBX, but can only connect the manufacturer's sets to their PBX, but the benefit is more visible information displayed and/or the benefit is more visible information displayed and/or specific function buttons. specific function buttons.

- - DECTDECT ( (Digital Enhanced Cordless Telecommunications)Digital Enhanced Cordless Telecommunications)

>> a standard for connecting cordless phones. a standard for connecting cordless phones. - - Internet ProtocolInternet Protocol - used for communicating data across a - used for communicating data across a

packet-switched internetworkpacket-switched internetwork. . For example, H.323 and For example, H.323 and SIP. SIP.

Interfaces for connecting PBXs to each otherInterfaces for connecting PBXs to each other include:include:

- proprietary protocols - if equipment from several - proprietary protocols - if equipment from several manufacturers are on site, the use of a standard manufacturers are on site, the use of a standard protocol is required. protocol is required.

- - QSIGQSIG - QSIG is an ISDN based signaling protocol for - QSIG is an ISDN based signaling protocol for

signalling between private branch exchanges (PBXs) signalling between private branch exchanges (PBXs) in a Private Integrated Services Network (PISN) for in a Private Integrated Services Network (PISN) for connecting PBXs to each other, usually runs over T1 connecting PBXs to each other, usually runs over T1 (T-carrier) or E1 (E-carrier) physical circuits. (T-carrier) or E1 (E-carrier) physical circuits.

- - DPNSSDPNSS - for connecting PBXs to trunk lines. - for connecting PBXs to trunk lines.

Standardised by British Telecom, this usually runs Standardised by British Telecom, this usually runs over E1 (E-carrier) physical circuits. over E1 (E-carrier) physical circuits.

- - Internet ProtocolInternet Protocol - H.323, SIP and IAX protocols are - H.323, SIP and IAX protocols are

IP based solutions which can handle voice and IP based solutions which can handle voice and multimedia (e.g. video) calls. multimedia (e.g. video) calls.

Interfaces for connecting PBXs to trunk Interfaces for connecting PBXs to trunk lineslines include include::

- - standard POTS linesstandard POTS lines - the common two-wire - the common two-wire interface used in most domestic homes. This is interface used in most domestic homes. This is adequate only for smaller systems, and can adequate only for smaller systems, and can suffer from not being able to detect incoming suffer from not being able to detect incoming calls when trying to make an outbound call. calls when trying to make an outbound call.

- - ISDNISDN - the most common digital standard for - the most common digital standard for fixed telephony devices. This can be supplied fixed telephony devices. This can be supplied in either Basic (2 circuit capacity) or Primary in either Basic (2 circuit capacity) or Primary (24 or 30 circuit capacity) versions. Most (24 or 30 circuit capacity) versions. Most medium to large companies would use medium to large companies would use Primary ISDN circuits carried on T1 or E1 Primary ISDN circuits carried on T1 or E1 physical connections. physical connections.

- - Internet ProtocolInternet Protocol - H.323, SIP, MGCP, and - H.323, SIP, MGCP, and IAX protocols operate over IP and are IAX protocols operate over IP and are supported by some network providers. supported by some network providers.

Interfaces for collecting data from the PBXInterfaces for collecting data from the PBX::

- - Serial interfaceSerial interface - historically used to print - historically used to print every call record to a serial printer. Now an every call record to a serial printer. Now an application connects via serial cable to this port. application connects via serial cable to this port.

- - Network PortNetwork Port (Listen mode) - where an external (Listen mode) - where an external application connects to the TCP or UDP port. The application connects to the TCP or UDP port. The PBX then starts streaming information down to PBX then starts streaming information down to the application. the application.

- - Network PortNetwork Port (Server mode) - The PBX (Server mode) - The PBX connects to another application or buffer. connects to another application or buffer.

- - FileFile - The PBX generates a file containing the - The PBX generates a file containing the call records from the PBX. call records from the PBX.

Numbering system that is used in the PABX Numbering system that is used in the PABX systemsystem

PABX used their own numbering system. PABX used their own numbering system. Bg internal call, user only need to dial the Bg internal call, user only need to dial the

extension no. This is because small switching extension no. This is because small switching system is applied in the company.system is applied in the company.

Low cost - internal call X no need to pay bill.Low cost - internal call X no need to pay bill. PABX system more than 50 line – 2 digit PABX system more than 50 line – 2 digit PABX system more than 50-500 line – 3 digit PABX system more than 50-500 line – 3 digit PABX system more than 500 line – 4 digit PABX system more than 500 line – 4 digit

depend to PABX capacity.depend to PABX capacity. No 0, 1, 8, 9 cannot be use as a starting No 0, 1, 8, 9 cannot be use as a starting

number.number. 0 – call operator0 – call operator 1 – service call1 – service call 9 – external call9 – external call 8 – Menarik panggilan 8 – Menarik panggilan

If the PABX not fulfill the SIRIM requirement, If the PABX not fulfill the SIRIM requirement, the PABX cannot market in Malaysia.the PABX cannot market in Malaysia.

Used DigitUsed Digit No FunctionNo Function

1X1X Service callService call

2XXX2XXX Nombor SambunganNombor Sambungan

3XXX3XXX Nombor SambunganNombor Sambungan

4XXX4XXX Nombor SambunganNombor Sambungan

5XXX5XXX Nombor SambunganNombor Sambungan

6XXX6XXX Nombor SambunganNombor Sambungan

7XXX7XXX Nombor SambunganNombor Sambungan

8X8X Tarik panggilanTarik panggilan

99 Membuat panggilan Membuat panggilan luarluar

00 PABX OperatorPABX Operator