Configuring a SIP phone to work with FreeSWITCH

Most of the devices that we connect to FreeSWITCH will be SIP-based. SIP or Session Initiation Protocol is a very common signaling protocol for telephone calls. (SIP is not limited to voice; it can handle chat, video, and other session types.) SIP phones come in two varieties: hard phones and soft phones. A hard phone is a standalone device with a headset, keypad, and usually a digital display. A soft phone is a software application that runs on a computer and utilizes the computer's speaker and microphone or an external headset. We will examine the setup process for a free soft phone called X-Lite, as well as the basic SIP configuration options for hard phones from Aastra, Polycom, and Snom.

SIP settings

All SIP devices have a minimum set of configuration parameters that must be set. Like all complex protocols, SIP has its share of obscure and sometimes arcane configuration options. However, they are well beyond the scope of this book. We...