There are different reasons why a set may not be registered to the extension number selected.
1. The extension number selected has not been programmed in form 9 as an IP set.
2. If there are keys programmed on the set in form 9 that exceed the number of keys on the set being registered. I.e. In form 9 the set by default is a 5020 set with a CO line key programmed on line 2, then a 5201 set could not be registered against that extension number. To correct this, delete any programming in form 9 for keys above the number of keys on the phone being registered.
3. The extension number is already registered and has a MAC address assigned to it. If this is the case, then using the set replacement feature code should work. |