Jerry,
Know that but in the programming manual it suggests that you can swap a digital extension for an analogue one and visa versa by going into the programming answering y to extension relocation and then plugging in the type of telephone you require, either a digital or an analogue, the system will recognise the extension (after changing the wiring on the line jack to suit). Aftre one minute the handset will be operational.
Rgds,
Doug