From http://wiki.vtiger.com/archives

About

vtiger is a open-source CRM solution. Asterisk® is an open source PBXi, telephony engine, and telephony applications toolkit which allows users to make and receive calls from software phones (softphones) using their computer. The vtiger-asterisk integration will allow users to use vtiger to create calls and receive notifications on incoming calls using the Asterisk Call Manager API provided by Asterisk. This document describes how to configure vTigerCRM to be able to use Asterisk with it.

Features

The following features are provided:

1. Make calls by clicking on phone numbers (links) within vtiger.
2. Provides notification within vtiger giving details of the caller when a call comes to the user. (Notification appears on the bottom right-corner of the screen.)
3. View all past calls under PBX Manager module (Tools => PBX Manager)
4. Associates the call with the Contact/Account/Lead record in Activity History section (in the More Information tab).
5. Setup user extensions through My Preferences (per user basis).

Requirements

• vtigerCRM 5.1.0 should be installed on your system
• You should have a Asterisk system running
• The servers running vtiger and Asterisk should be visible to each other
• You have a valid asterisk user extension and a softphone configured to that extension.

Configuring Asterisk

This section explains how to configure asterisk to work with vtiger. There are some minor (in some cases even none) changes that you require to achive this. Follow the link here on how to configure asterisk to work with vtiger.

Configuring vtiger CRM

Once you have setup asterisk server to work with vtiger, you need to configure vtiger settings so that it can connect to asterisk. Its easy with the steps we explain here.

Setting User Extensions

vtiger allows you to create extensions for each user. These are the asterisk extensions that when configured in vtiger let you call (or receive call) for that user. We explain it here on how to set user extensions in vtiger.

Making Outgoing Calls

So, you are done setting asterisk and vtiger. Start making some calls. Read more here on how to make outgoing calls using vtiger.

Receive Incoming Calls

Outgoing calls achieved. Next step - get incoming call notifications. Click here to know how to achieve this with vtiger.

Number Formats

It is possible to save the number (in vTiger) in any format (with or without prefixing extensions like SIP, PSTN etc.) and create the call. vTiger should recognize the caller in case of incoming call as long as there is a separator “:” between the prefix and the number i.e. like SIP:211 (no spaces). In case there is no prefix specified, the default context is picked for the call

Note: It is recommended not to use any special chars or spaces in the phone number field.