Business telephone systems have been a long time in their development to where they are today, developing from unmistakable solution systems requiring involved phone commodities to virtual PBX ( private branch exchange ) existing in cyberspace and functioning in tie with a companys existing data transfer.
Some of the original popular phone systems were the 1A2 Key System. These varied well and had a firm grasp on the market for many oldness around the 1950s. The KSU ( Answer Service Unit ) acted as a central qualification unit and calls were redirected from efficient via a veritable mechanism contained in the phone. This permitted bottom line jibing as intercom services and grasp constitution with music. These manageable being could be achieved on a line by line basis by hardwiring a backplane into the central management unit. A headlight quality for each line allowed users to briskly nail down the level of all phone lines accessed by their phone.
PBX was first used to describe such key systems where switchboards were run by hand. PBX gradually started to use automated systems instead of operators. As this became more common, the terms PABX ( private automatic branch exchange ) and PMBX ( private manual branch exchange ) came about to differentiate between the two systems. EPABX ( electronic private automatic branch exchange ) was also used to describe various digital systems.
One of the main reasons for such systems was to reduce the cost of internal calls, since calls could be made over the private branch and not incur local call costs. As the systems developed, other features such as extension dialling, call forwarding and various forms of line hunting became available.
The next major development was with the rise of data networks and the internet. Since many companies already had packet switch networks due to the need for data transfer, it became viable to use a phone line over their existing data connection and hence VoIP ( Voice over Internet protocol ) came about. Far from perfect, VoIP to this day can still have issues with latency and power cuts which can render it inoperable.
VoIPs main advantage, however, was its cost. This is due to the way data is charged compared to standard phone connections. Typically, a phone connection is charged on a connection time basis, so there is a charge regardless of data transfer. Packet switching connections, however, tend to charge based on the number of packets ( or amount of data ) being transferred, which, even under high load, tends to result in much lower costs.
Since many systems were now operating via data connections, it was recognised that many companies didnt have requirements for large in - house PBX systems, and as such, hosted PBX came about. A hosted PBX system is a service whereby the phone system is a service and requires no capital investment in the hardware needed to run it. This is particularly advantageous for smaller companies in several ways; often such systems are very easily scalable. With hosted systems, companies can simply increase or decrease their contract instead of buying a system which is larger than their needs and paying a large amount of capital or later having to expand their system in house.
Thus PBX is a term with a myriad of meanings. Having started as manually operated switchboards and going through several phases of development to modern day telephone systems, the term is now used to describe many complex telephone systems, where often there is in fact no private branch, and no exchange.
