| Private branch exchange (PBX) is a telephony system | | | | 5. Place external callers on hold while waiting for |
| used within an organization that serves a particular | | | | a requested person to answer, and playing music or |
| business or office and runs on a server and is | | | | customized commercial messages for the caller |
| accessible as well as compatible with the Local Area | | | | waiting. |
| Network (LAN). An organization within a PBX, has | | | | 6. Provide system call management features. |
| purchased, allotted or leased specific numbers to be | | | | 7. Transfer calls between internal departments |
| used for many businesses or for the general public. | | | | or extensions. |
| PBXs are also called as: | | | | 8. Record voice messages from an external |
| PABX: private automatic branch exchange | | | | caller for any extension. |
| EPABX: electronic private automatic branch exchange | | | | A PBX will include: |
| Important technical roles of a PBX: | | | | • The PBX’s internal switching network |
| 1. To switch between telephone users thereby | | | | • Switching and control cards, Logic cards, |
| creating connections | | | | power cards as well as related devices to facilitate |
| 2. To properly end the connection when a user | | | | PBX operation |
| hangs up | | | | • Microcomputer or Microcontroller for |
| 3. To make sure the connection remains in place | | | | arbitrary data control, processing and logic |
| properly by keeping its resources | | | | • Telephone sets, sometimes called lines |
| 4. To record the quantities, statistics and | | | | • Switchboard or Console allows the operator |
| metering related to the calls | | | | to control incoming calls |
| Functions of a PBX are: | | | | • Outside Telco trunks that deliver signals to |
| 1. Provide to external callers a number so that | | | | (and carry them from) the PBX |
| they can use to access all persons in a company. | | | | • Uninterruptible Power Supply (UPS) |
| 2. Automatic call answering, but offering options | | | | consisting of power switches, sensors and batteries |
| from which a user can select to be directed to a | | | | • Cabinets, vaults, closets and other housings |
| specific department. | | | | • Interconnecting wiring |
| 3. Distribute calls to employees in an even way | | | | So, we can also define a PBX as a switch station for |
| by using the Automatic Call Distribution (ACD) | | | | telephone systems. It consist mainly many branches |
| feature. | | | | of telephone systems and switches connections to |
| 4. While answering calls, it allows the use of | | | | and from them, thereby linking phone lines. |
| customized business greetings. | | | | |