From InterceptRadio.com Wiki
Here are some notes related to how I converted a Cisco 7960 phone to a SIP image.
Once this is done the 7960 will work as a standalone SIP phone.
I tested it by using a crossover cable to directly connect the 7960 to a laptop running SipXphone.
echo -n "text" >> file
will write a line of text to the end of a file without adding the newline character. (need to do this for OS79XX.TXT)
**# to unlock phone config
**#** to reboot phone
put static ip & tftp server ip into phone config
switch from P00 and P0S filenames each time you upgrade
P00303010102 (may need to shorten filename to 8 chars)
P0S3-04-3-00 (last version of unsigned code)
menu 9 to unlock, password: cisco
disable dhcp, put static ip & tftp server ip into phone config
P0S3-06-3-00 in both OS79XX.TXT and SIPDefault.cnf (need both bin and sbn for this upgrade)
P003-07-4-00 in OS79XX.TXT and P0S3-07-4-00 SIPDefault.cnf (need bin, sb2, and loads + P003 bin & sbn for this upgrade)
phone will do a two-step load process