PBX - Private Branch eXchange
Most medium-sized and larger companies use a PBX because it's much less expensive than connecting an external telephone line to every telephone in the organization.
Without a PBX, a company will need to lease one telephone line for every employee with a telephone.
In addition, it's easier to call someone within a PBX because the number you need to dial is typically just 3 or 4 digits.
PBXs are also referred to as:
- PABX - private automatic branch exchange
- EPABX - electronic private automatic branch exchange
A telephone switch that supports VoIP is called IP PBX.
One of the main advantages of an IP PBX is the fact that it employs converged data and voice networks. This means that Internet access, as well as VoIP communications and traditional telephone communications, are all possible using a single line to each user. This provides flexibility as an enterprise grows, and can also reduce long-term operation and maintenance costs.