Now that we have decided on our PSTN interconnection, we need to decide on our internal connections. Our PBX can have modems, fax machines, hardware and software telephones, and other PBXs connected. We will refer to all these different machines as terminal equipment.
There are four major types of terminal equipment—hard phones, soft phones, analog adapters, and PBXs. We will cover each type briefly.
The term hard in hard phones is the short form of hardware. Hardware phones are physical devices that act as a telephone handset. Hard phones are available for POTS (as used in the typical household) or VoIP. Hard phones will typically deliver the highest quality among types of terminal equipment. The most popular hard phones in the market today are:
Voice over IP uses various protocols depending on the handset...