I've resently change a 6x16 DR5 to an 8x24 DR2, the programming has been setup as before. Problem is the 2 doorphones, they work , except that you can't hear the caller. They ring the set, you can open the door etc. I've checked to make sure prime line is set to intercom. The programming is the same as it was on the 6x16. Is it a software issue somehow, even though the doorphones do work??? The person at the door can hear the person inside.