I installed a new system for a customer that wanted to use some of his older phones with the new system. The problem I'm faced with is that the T7220 phones do not ring on incoming calls. I've put them in the incoming call group with the other phones in the system, but they do not ring. As a matter of fact, they cannot answer the call on any of the T7220's. When there is an incoming call, the phones light up, and when you try to pick up the call, there is a busy signal. Is there another location that I need to activate the extensions in order to have them work like the DT343 phones?
Thank you in advance.