Voip Desk Phone - Use with the Asterisk Server as a Console Phone

After setting up a small Asterisk Voip Server, it occurred to me that the Voip Desk Phone detailed in these pages could be used with an Asterisk server as a Console Phone.

Asterisk will use the server's Sound Card if it has one as a phone. This is often used (when set to auto answer) as an intercom - An extension is configured to dial the console and anyone can speak to whoever is sitting near the asterisk box by dialling the extension.

To use it as a regular phone, it is necessary to log in to the Asterisk Server and issue 'dial' and 'hangup' commands to start and end a call.

In order to use the Desk Phone with Asterisk, the server has to be configured to allow a login via the serial port from a user that has permission to run 'asterisk -r'.

The Desk Phone firmware will have to be compiled with the username and password of the 'asterisk' user, for this reason, a bin file has not been provided, the source code for the .main.c' file is main.c, just replace the 'main.c' file from the original files.

When switched on, the Desk Phone sends a User name, Password and then 'asterisk -r'. The phone does not check to see if the commands were successful, a terminal logged in to the asterisk server running in diagnostic mode ( -vvvvvc ) will show when the phone logs in. You could also lift the handset and dial a number.

The first call you should probably make is to the (in a standard asterisk setup) echo test, to verify that the sound card mixer is set properly. On my system - using a Slackware and a Creative Sound card - a combination of mmix and alsa-mixer allowed me to get the mic and speaker levels set.

The new firmware buffers keys when the handset is lifted, if no further keys have been pressed after a few seconds, then 'dial ' followed by the buffered keys is send to the server. If the handset is replaced, 'hangup' is sent. The mem key dials extension 9000 (that my asterisk server uses as a voice mail login).

As there is no audio feedback from the phone that a number is being dialled (asterisk does not emit a dial tone to the console), the phone's led lights normally when the handset is lifted, and then brighter when keys have been pressed, returning to normal brightness when the dial command has been sent to the Asterisk server.

Wiring Diagram for the Voip Desk Phone

Introduction
About the PIC Processor
Programing the PIC
Building Blocks
PIC Test Rig

Connecting an LCD
VoipDeskPhone
VoipDeskPhone the Software
VoipDeskPhone3 Changes for use as an Asterisk Console Phone

Cheap PIC Keypad PoundShop Clock / Alarm = Cheap Keypad

3 State LEDs

Add DRAM to a PIC
PIC Links