PBX refers to Private Branch eXchange, a private owned multitasking exchange system that is being popular in the small and big institutes and corporation houses because of its low cost and multifunctional performance. It is a telephone line connected usually in the controlling office or in reception houses that transfers the incoming calls to the concerned person or desired no as well as it also controls the outgoing calls because without the prior permission of the PBX office the insider can not call from the office or institute. For outside calling, the caller has to dial the existed code of PBX then he/she will be allowed to call outside beyond its network as PBX get dialed the desired no. This device saves lots of money as the owner has to pay only for the granted connection e.g if there are more than 1000 telephones in a office and there are only 50 connections are available for that office, it owner has to pay only for the 50 connections not for the 1000 phones, because only 50 routes are being used for calling outside beyond the office network.
If someone wants to talk the CEO of the company and does not have his/her direct no, the caller have to dial first the controlling office no and then he/she will has to ask for the extension no of the CEO. Thus the only one line is being used and the callers do not need to learn all the numbers except the PBX office no.
PBX has several other advantages like it has call forwarding, conferencing, inter-coming, transferring and voice mail as well as caller ID facilities. PBX controls on the unwanted incoming calls that is used for either making irritated or for promoting unwanted product. It also controls over the out going calls that can dialed or not dialed without the permission of the PBX controlling room. So this device has several advantages, that’s why it’s being the back bone of any company’s telecommunication department.