atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems How do I Hook up Ringer on old GTE 1A2 Phone

I recently found a few old GTE Multi-Line Phones. After doing some research I think they are called GTE Electric 186 Key System, and use a 1A2 system. I have been trying to hook up one of these phones to a normal phone line. I managed to strip apart a RJ11 cord and get the phone to have a dial tone and dial out. Using the red and green wires. But I cant seem to figure out how to get the ringer to work. When I call the phone from my cell phone and pick up the receiver it answers the call but the phone doesn't ring. Any help would be greatly appreciated

I'll try to dig up the prints for the phone, but in the mean time, trace the wiring from the bell. You should have two wires that connect to the yellow/slate pair. Remove them from their termination point and move them over to the dial tone pair. That should get it ringing.

Sam

That would be great. I will try connect the wires like you said thanks for the help.

https://www.telephonecollectors.info/index.php?option=com_docman&task=doc_details&gid=1879&Itemid=31

Sam is correct. They have the same color code as a typical WE key set. Slate/yellow pair is the ringer circuit.

Well I found the yellow/slate wire but it leads to the Lamps. I found the ringer and it has 4 wires connected to it that are blue, red, black, and green. should I try connecting the green and red to the dialer pair? And thanks for the schematic Arthur.

Ok I disconnected the red and green pair and connected them to the dial tone pair and it seems to be working now. Thanks for the help.

I doubt that it will work if you did what you say you did.

If you remove the Red and Green ringer wires from where they were connected (in a new, stock, telephone, they should have been connected to a pair of screws where the yellow/slate and slate/yellow mounting cord leads were terminated) and then connected those leads right across your dial tone pair, you would be putting a short circuit across the pair, and you would get a pre-trip on incoming calls. Doing it the way you say you did it eliminates the ringing capacitor, which is required in the circuit.

Go back and do what we suggested:

Find the incoming mounting cord leads that are yellow/slate and slate/yellow. Remove the internal wires that are terminated on those two screws. Move those two wires to the incoming Tip and Ring of your dial tone pair.

The forum software is not allowing me to edit my remarks. Let me try again to explain what you should do:

Every single-line ringer needs to have a capacitor in series to block the -48 Volt DC talk battery and allow the 90 V AC ringing current to pass.

The red and green ringer leads, in a stock, unmolested, telephone, are connected to the following:

Red goes to terminal RR. The slate-yellow mounting cord lead is also terminated there.

Green goes to terminal 8. That is one side of the .47mFd ringing circuit capacitor.

The other side of the capacitor terminates on terminal 10. There is a black strap (double ended short wire) that connects terminal 10 and terminal RT. On terminal RT should also be the yellow-slate mounting cord lead.

To change the ringer from Common Bell wiring to single-line wiring, you need to take the red ringer wire and the black strap off of RR and RT, respectively, and put them across the two leads that have the dial tone on them.

You were right, i only had a second to test what i did and it seemed like it was working. But after testing it again I noticed it wasn't ringing right. After doing what you said and hooking everything back where it was and hooking it up using the single-line wiring the bell is working great. Someday i would like to get it up in running like it was meant to used. From what I researched I would need something called a KSU. The building I found these in has all the original wiring for the original cable attached to the phone, so they can hook right up. My question is what is a KSU and which one would i need for these phones? Thanks again for all the detailed information and help.

KSU = Key Service Unit.

The phones are called "key" telephones because they have keys that select the lines. In historic terms, a key was any electrical switch that a subscriber (now we say customer) actually put his hand on. A switch was (and is) a piece of switching equipment, such as a Central Office switch, and a button was a momentary key. The terms have gotten blurred, along with hundreds of other terms in the industry.

The brain that controls the phones was, historically, and is at present, called a Key Service Unit. A KSU uses electricity from an associated (or built-in) power supply. The power supply creates voltages needed to make the phones ring, light up and place calls on hold.

That said, you need a KSU that can support 1A2 phones. (pronounced one ay two).

See, for example,

https://www.frillfreephones.com/1a2technology.html

The smallest is called a "shoebox" and is the 551B or 551C KSU made by Western Electric. It supports up to 4 CO lines, or 3 CO lines and a manual intercom. There are other ones made by WE and by other companies, and they get bigger to support more central office lines and bigger intercom systems. They can be interconnected to create huge systems. I worked on one system that served 12,000 telephones, 6,000 lines, and several hundred intercoms.

Look on Ebay for "1A2 KSU" If you donlt find what you want, contact me privately by email: info (at) SIBTA (dot) com.