I have an iDCS 100 system I am attempting to restore. MGI3 card installed and configured properly with network address also with extensions 3201-3208 configured for IP phone sets. When attempting to connect either an ITP-5021D or ITP-5121D phone to the system results in a "Registration Lock" error on the phone. Phone parameters have been set correctly with the Server IP, System ID, Password, etc. Any thoughts on what is causing the registration lock on these phones and how to correct it? Thanks in advance.

There's a setting in mmc841 from memory, where you can enable/disable ip phone registration. I can't remember if it's in the 100 or only 7000 series.