What is PBX? It stands for private branch exchange, and is a phone system that many companies are using today, regardless of size. It is one of the most cost efficient ways that a company can run multiple phone lines without having to have independent lines for each handset.
When it comes to how outgoing calls and extension-to-extension calls, what is the job of PBX? Well, both calls are handled the same way at first. The caller picks up the phone and the system acknowledges it, and then the line circuit establishes where it is coming from. The control center detects the initiation, and then decides what type of service the activated line requires. It links to the specific receiver using information that was retrieved from the control. Dial tone will start on the line and the caller can enter the phone number. The PBX control identifies the number and matches it to its coinciding line. The line is tested to see if it is available. If the line comes back as available, the caller hears the ring back as the handset on the other end starts to ring. The line is then monitored to see if the other party answers. Once it is answered, it sets up a calling-to-called path so the two people can talk. The line remains monitored until the conversation is over and handsets are hung up.
Outgoing calls are handled in much the same way, but the control will connect to one of the multiple trunks at the local central office. This system can also track call statistics and valuable billing information.