Allen Telephone Wiring & VoIP

This past holiday season I received as a white elephant gift an older outdoor weatherproof telephone by Allen Tel. Prod. From what I could tell this phone was used at the local community college by the campus police. Unfortunately, I wasn’t able to find a whole lot of information on this model, and its lack of a dial limited what I could do with it.

After it sat idly for a couple of months, I decided I could use it to link my workshop and house together. I already had a payphone from the 80’s sitting in my workshop, and figured that if I created an Asterisks installation then these phones could talk to one another over VoIP. Before we continue, I just wanna reiterate that CRT’s are dangerous, and have the potential to fatally shock you, so make sure you know what you’re doing before disassembly, and be careful!

My plan was to use a Cisco SPA112 adapter on both ends to convert the analog phones to VoIP. I naively thought that the Allen telephone would have a standard RJ11 connection inside of it; however, upon opening up the telephone I was faced with a myriad of screw terminals. Since I couldn’t find the proper documentation for this phone, I decided to poke around inside with a stripped RJ11 cable connected to the VoIP adapter while keeping the headset pushed up against my ear. After a few false positives, I discovered the correct combination.

Pictured above is how the connection was made. The green wire goes to a block that looks like “L2” and the red wire goes to the “K” block. I bought an RJ11 to spade terminal cable off of amazon to make the connection cleaner. I then electrical taped the black and yellow wires to prevent them from making any accidental contact with other parts of the board.

Now all I needed to do was connect everything to Asterisk. For this I used the FreePBX Linux install to handle installing Linux and configuring Asterisk. There are plenty of tutorials online that explain this process, however; the gist of it is, after installing FreePBX I configured two extensions, one for the shop, and one for the house. Then I configured the Cisco SPA112 adapters to connect to the FreePBX server.

The only snag I ran into was entering the password into the SPA112 to authenticate it to FreePBX server. On the FreePBX box, in the configuration section for the extension there is a “Password For New User” and there is also a text box labeled “Secret”. I originally was putting in the “Password For New User” into the password section on the SPA112; however, I should have been using the “Secret”. After I resolved that both SPA112’s authenticated and I was then receiving dial tone on both phones.

I was able to call the phone in the house from the payphone in the shop because it had a touch-tone dial on it; however, on the Allen phone, it didn’t have a dial on it at all. To get around this I configured the Allen phone to dial the shop automatically when the handset was lifted off the receiver. It took a little bit of trial and error, and some thorough googling, but I eventually discovered how to configure the SPA112 to do this.

By adding |S1<:100> to the end of the dial plan of the SPA112, I was able to have it automatically dial extension 100 (my workshop) when the handset was lifted from the receiver. For example, if my existing dial plan was (*xx|[3469]11|0|00|[2-9]xxxxxx|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.) then to have it automatically dial an extension I would change it to (*xx|[3469]11|0|00|[2-9]xxxxxx|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.|S1<:100>)

This has become a fun way to communicate between the house and workshop without having to venture into the Arizona heat.