From: Jiri Kuthan [mailto:jiri@iptel.org] [snip] PIN Lock -- use phones which can log-off and log-on (I'm not aware of any now -- only 3com used to do that)
The snom 100 IP phones that we test with have a mode known as the "Logon Manager" mode. It permits the phone to be registered and unregistered as required. I think that fits the bill nicely. http://snom.de/
Cheers, Alan alan[at]jasomi.com