Hi Leo,
This timeout for Personal Directory was fixed starting in the CUCM versions listed in this Bug/Feature request;
CSCsd91156
CM5.0 - Personal Directory Enhancements.
Symptom:
CM5.0 Personal DIrectory login from the phone has a timeout value of 30 mins
and the users have to login again after the timeout.
Please add user-defined timeout and zero timeout capability
Workaround:
Users must login using Userid/PIN until this feature is integrated
This information (below) was nicely provided by Java @ Cisco
In the CUCM Versions listed in the Bug Id CSCsd91156 "Log Out" feature has been added in the personal address book which will prevent the auto log out and a user will always remain logged in until a users hits the "Log Out" option.
Hope this helps!
Rob