I did the same thing that Sam mentioned, but I used 1A1 relays and other misc. 6A intercom apparatus to make it happen. Those things are so easy to wire however you wish. My reason for doing this setup was because I had a mix of single line and key sets in my house. It wasn't graceful to operate, in fact there really wasn't anything that could be done except to answer or place outside calls (no call transfer, etc.) but it was really more of a hobby setup than anything.

Hint: The 237B is one of the most versatile KTUs for applications such as this since it was designed for conferencing of lines.


Ed Vaughn, MBSWWYPBX