Are the Pap2t devices set to re-register every 60 seconds like the ht 502's? It would seem that I might be missing incoming calls while the ht 502 is re-registering as it takes some time to re-register. I realize that outgoing calls may not need to be registered, but it seems like ultimately it would be less of a chance of missing calls, if my device is unavailable for 10-15 seconds each minute...But then again, maybe I don't quite get the way that works...