The industry terminology for this is a PBX (Private Branch Exchange).
This is a piece of telephone switching equipment that allows telephone extensions to connect to each other and in turn the users to talk to each other.
Hosted Telephony Solution
In the hosted telephony solution the only equipment that is needed at the business office is the phone. These phones are IP (Internet Protocol) enabled to handle SIP (Session Initiation Protocol). The phones connect direct to the Packnet Network registration servers and are subsequently allowed to make telephone calls.
This setup allows the phone to be controlled from one central location and through one central system, the Metis online portal. If an office has more than one office this model can be replicated as many times as is required.
Multi Site Hosted VoIP Telephony setup
In this setup all offices are connected to the Packnet Hosted Telephony Network. This means that calls all calls between the office are free. This means that calls can be routed to any of the phones at any of the sites as required. The sites can be in different locations or different countries if required.