Setting up PBX without T1/analogue lines


Is it possible to setup PBX without outgoing/incoming lines? I am trying to setup PBX in a lab so that IP phone may dial each other. I am using cisco 7960 and phones are loaded with SIP firmware version 7.2. I have two phones connected with asterisk box and they are not able to dial each other. I think I am confusing line and extensions. Please help.

Thanks in advance.


Sure it is.

I don’t use Cisco phones so I can’t help you more, sorry.


Marco Bruni

It is probably a configuration issue. Do your phones register ? Pleas post the output of your CLI when you try to make a call as well as your extensions.conf and sip.conf


Thanks for your reply. Yes my phones register. Below is the sip.conf and extensions.conf


exten => s,1,Verbose(1|Unrouted call handler)
exten => s,n,Answer()
exten => s,n,Wait(1)
exten => s,n,Playback(tt-weasels)
exten => s,n,Hangup()
exten => 500,1,Verbose(1|Echo test application)
exten => 500,n,Echo()
exten => 500,n,Hangup()
include => internal

My phones are showing line 1000 on display. Whenever I try to use any of the phones display shows line 1000 in use. I am not able to dial. Please guide and help.


Your phones are set up to use the phones context. Now in the phones context you have include => internal which includes everything that is in the internal context. In the internal context all you have is extension 500 which is an echo test.

To call between the two phones you would want to add to the [phones] context or the [internal] context.

Exten => 1000,1,Dial(SIP/1000)

This tell asterisk that if some one dials 1000 to call sip account 1000.