In my recent post on configuring a Cisco IP phone for VoIP using SIP, the RINGLIST.DAT file pointed to a file called CTU.raw – a custom ringtone for my phone. I hadn’t realised at the time but CTU is something to do with the TV series “24” and had been passed over to me with the rest of the configuration files that I used for reference. If you want to generate your own ringtones it’s quite simple but beware – there is not room for anything more than a few seconds.

I followed Jozef Janitor’s advice to create a custom ringtone, using the SoX Wrap to generate a .RAW file from an .MP3 on my Mac (I can handle the command line but SoX Wrap is also an easy way to get sox into Mac OS X). If you don’t use a Mac then Leigh Harrison offers some alternatives in his blog post on the subject and Josef’s advice suggests some others. Unfortunately though, even after truncated the file to 16KB using dd it was too long and when I tried to select it the phone displayed Custom Ring Unavailable!. Chopping it down to 15 bytes seemed to work but that left a very short clip indeed (about 2 seconds).

If you’re after a good source of pre-recorded tones, then try The Caretakers’ Website or here. I found that, including the two built-in tones, my 7940 only offered a choice of 50 tones.

Incidentally, RINGLIST.DAT is one supported file format but you can also use an XML file (as described in the Cisco Call Manager documentation for custom phone rings).

If your IP phone is in a work environment, the chances are that the administrators won’t let you add your ring tones to the system. Logan Ingalls found a workaround by using his own TFTP server but I have to warn you that they probably won’t like that either!