I'm having a problem with a existing 1416 set in port (8)on my IP500 Digital Station. I need to change it to a 1408 set and when I remove the 1416 and plug the 1408 into the port, it doesn't reconize it. It says Unknown digital handset. I've tried rebooting, outing the user programming, but it just dosen't see it. Can someone please help. The system is IP 500 v2 8.0 (44).