Configuring Cisco 7940 for SIP

I spent a lot of time trying to install SIP on the Cisco 7940 phone, it comes with something called SCCP (or Skinny Call Control Protocol) installed as default. However you can (with some effort as I found!) install SIP and connect to a SIP network, such as Sipgate or Voipfone. I scoured the Internet and found bits and bobs on various sites, but none of them really explained EXACTLY how to do it as a process. Below you’ll see steps of how to do just that, along with a nice zip file for the config & a few ringtones.

1. First of all you need to download and install a TFTP server on your computer, the one I used is TFTPD32 for Windows, but other software is available for Mac or Linux.

2. Next make sure the settings are as so: Current Directory should be a blank folder on your desktop, call it something like Cisco & navigate to it. Next click settings. Only have TFTP Server & DHCP Server checked. On TFTP tab set the Base Directory to your Cisco folder on your desktop. TFTP security should be set to none. On the DHCP tab change the IP pool start address to the start of your home or office network. Mine is set to, set Size of pool to 5. Def. router (Opt 3) should be set to the IP address of your computer (where TFTP32 is install). Then set Mask (Opt 1) to (or whatever your subnet mask is). Click OK.

3. Next on your phone go to Network Setup and change the TFTP server to your computers IP. You might need to unlock the settings by using that option in the Settings menu. While you’re in there make sure your Router is set to your home or office router so it can get an IP for itself.

5. Download this zip file and extract it to your Cisco folder.

6. Change the file SIP%MACADDRESS%.cnf to whatever the MAC Address is on your phone (you can find this printed on a sticker underneath the unit).

7. Change the settings of the file to match those of your SIP provider, for a demo I am using – change the username, password and providor to your own.

8. Open SIPDefault.cnf and again change the provider settings to your own (again I am using as an example).

9. You can play about with the ringtones, I have included a couple in there to get you started. I won’t go into how to create your own, do a Google search and you can find out how, there’s a few more here. Within the SIPDefault.cnf it is linking to a newer Cisco logo located on my server using the parameter “logo_url:”, again you can change this to whatever you like. If you don’t want to change the operator logo, comment it out using #.

10. Restart the phone (rather than yanking the power cable out, hold down *, 6 & Settings). It should get an IP, connect to your TFTP server and try to install the latest firmware, along with the config files.

And that my friends should be it, you should be able to make and recieve calls using SIP. I’ll be honest with you, it was a complete ballache to get this far but hopefully with this guide, you’ll be a litte bit clearer on the subject.

Good luck!