I have a C-1000B Door Entry System and a call box. I don’t know the model of the call box but it only has 2 wires coming out the back of it if that is any help. I have a station on my PBX programmed as a ringdown and have that connected to the C-1000B where it says “Phone Line Input”. I push the button on the call box but nothing happens? I connect a butt set to my ringdown line, go off hook and it rings down fine so why doesn’t the C-1000B and call box work?