Monitor log of phone/user

I’ve got asterisk 1.8.7 logging to syslog using the command:
syslog.local5 => notice,warning,error,verbose in logger.conf.
I would like to filter the log so it debugs what is happening on a particular phone. I use cisco 7940 loaded with sip software but these phones can’t log anything on their own and I’ve been told the logging must be done by the controller machine, which in this case is asterisk. If I do ‘sip set debug on’ I get loads of debug material I don’t need. Is there a way to log just the phone?

Type “help sip set debug” at the CLI prompt.

How do you actually enable the sip debug?
When I do what you say i get: No such command ‘sip set debug’

It’s been awhile since I’ve worked with asterisk, but the last version I think 1.4 had this command.
Unless I’m missing something, this command doesn’t exist in the 1.8.9.
Do I need to install another package or something to get this command working?

I don’t know about 1.8, but for 1.6, you must include chan_sip during menuconfig. It should be included by default. Of course, if you don’t have chan_sip, you won’t have any SIP calls, and sip debug won’t be of use to you. The OP said they were using sip set debug, so they presumably do have chan_sip.

Incidentally, you should never use PM for asking questions. They should always be on the public forum.