Cisco 7940G with Asterisk

I have got Cisco 7940G IP Phones with the following firmware version.

App Load ID

Boot Load ID


  1. I want to use them with Asterisk 1.6. What do i need to do? Do i need to change the SCCP software to SIP for use with asterisk? if so, then is it possible to upgrade from this version directly to SIP Ver 7.5 firmware (P0S3-07-5-00, i got this firmware).

  2. What is skinny file meant for in asterisk? can the cisco ip phones be used the way Nortel are used through unistim.conf?

  3. What is chan_sccp? is that a solution to my problem?

chan_sccp is a direct implementation of the native Cisco protocol, but it does not get the level of development and support that goes into chan_sip.

I don’t personally know of restrictions on updating particular Cisco phones.

You are suggesting that i should update the phone firmwares from Cisco SCCP to SIP. Thanks for the support.

yes I use cisco 7940G’s on asterisk 1.8 and I upgraded them from cisco sccp to POS3-8-12-00. This page might help you…
to upgrade the phones try this: … 4584.shtml

Cisco sip software for 7940/7960 is a joke. SCCP provides way more features.

@tonj Thanks a lot for the support. Got the SIP firmware on the phones. I was trying to upgrade from factory shipped SCCP 3.1 MFG2 directly to SIP ver 7.5. i was getting error. i first upgraded to SIP ver 6.3 and then to SIP 7.5. They are working fine now.

@thor i will look for those features. thanks.