Hi Edward,

The 7945 will hold 100 entries for each of the Missed,Received and Placed Call History directories. The last entry in the list, (number 100) will be over-written as a new call record takes its place. As far as resetting or disconnecting the phone goes, different IP Phone models display different behaviour when it comes to this question as the (Call History) is stored on the IP Phone itself . Older models like the 7940/7960 series will lose the Call History when they have been disconnected, but newer models like the 7942/7962 or 7945/7965 series will keep their Call history when they have been disconnected :)

Hope this helps!

Rob