Not to hijack this thread, but this is in the same vein. I use the IP Softphone feature (road warrior mode) with my desk phone all the time as I "telecommute' or work at different location about 2 days a week. I find that when I log into my softphone the display on the desk phone disappears as the softphone assumes the identity of my desk phone (I believe this is normal). However when I log out of my softphone, it consistently takes 45-60 minutes for the display on the desk phone to return.
Is this normal, or how can I speed up the process? (This ususally isn't an issue as I can't be in two places at once, but it is annoying when I sometimes use the feature from a conference room on the other side of our building which is only a couple of minutes walk from my desk.