IPX 500.
Have a viking relay to electronic lock on front door.

Viking box connected to viking cpc.

User presses button on viking box, calls boss group to 2 reception phones.
They press a button to let the visitor in, hang up.
The cpc disconnects the call.
Viking unit hangs up, flashes, then rings the boss group back.

Still happens when viking box is swapped out for a plain old single line wall phone.

HELP!