Asterisk: The Definitive Guide, 5th Edition

Chapter 5. User Device Configuration

I don’t always know what I’m talking about, but I know I’m right.

Muhammad Ali

It’s time to connect some SIP user devices to Asterisk. While we are going to focus on the Asterisk end of things, keep in mind that defining a channel in Asterisk for the device to connect through is only half of the configuration; you also need to configure the other end—the device itself (usually a phone)—so it knows where to send its calls.

An Important Note About SIP Endpoints

Configuring the other end of the SIP relationship is of course necessary, but is not part of Asterisk configuration, and ultimately is out of the scope of this book. There must be thousands of different types of SIP endpoints in the market, including desk phones, softphones, PBXs, proxy servers, conferencing servers, and all manner of other products. Each manufacturer has its own tools to allow you to configure its products (and some of them require extensive knowledge). SIP is a complex protocol. Having said that, most SIP desk telephones have some sort of web interface, and most softphones have a configuration menu built into their GUI.

At its simplest, configuring a SIP device involves providing three parameters:

• Address of the server it’s going to connect through (your Asterisk server)

• Username (which could also be called the subscriber name, extension, or something similar)

• Password

While each type of endpoint is going to be different, they’ll all follow a similar convention, and while there ...