Western Electric phones were built to last. That’s because originally, these phones were never sold to the phone subscriber, but leased. When the phones were returned, they were just refurbished, and given back out. Likewise, these phones are generally going strong after 50 or more years of duty. They will however develop a few glitches.
The engineering of the land line phone is something quite remarkable. The basic design dates back to the 1920’s, and changed very little over the years until the breakup of AT&T in 1984. While high-tech wireless smartphones capture peoples attention these days, they are limited by batteries that must be recharged, and iffy wireless signals. A geek like me is more amazed at the remarkably simple, smart design of an old land-line phone, and how they do so much, with so little. These phones are designed to operate on only 2 thin wires, need no external power, and can amplify the tiniest signals loud enough to clearly listen to. From those mere two wires, you can communicate with anyone anywhere in the world! Prior to cell phones, having a call randomly disconnect, or have poor audio quality was a rare thing, and land line phones almost always worked, even when the power was out.
Touch tone was developed in 1963, and with it, the first transistor was installed into a phone on the touch tone pad. While these old phones rarely ever have problems, the touch tone oscillators were a little bit more complex than the past rotary phones, and there are parts that can drift out of adjustment in the 50 or so years since they were manufactured. The result is that you cannot dial out, or you end up dialing wrong numbers, despite being positive you dialed it correctly.
Adjusting the touch tones is actually quite easy if you are handy with tools, and working with basic electronics
Here are some of the tools and supplies you will need:
A flat screwdriver to disassemble the phone and unscrew wires
A 9-volt battery to power the phone while you are testing and repairing it
A multi-meter or other device that can measure frequency
Clip leads to connect the meter, and the battery to the phone
plastic electronics calibration tool with triangle or slotted screwdriver end (available at Radio Shack)
(optional) a female telephone plug
I am showing the procedure with a wall phone model 2554, the procedure is largely the same for the desk phone counterpart, and even the “Princess” phone and if you’re lucky enough to have an old payphone, those too. The newer “Slimline” phones are slightly different however. I purchased this phone on E-bay for $20. and when I put it on the wall, I found out I could receive a call, but when pressing any of the buttons, the phone company would not even register that I had pressed a button
The way “touch tone” works is by overlaying two tones together in sort of a “grid” with the keypad. All the buttons in the same vertical row generate the same tone, and all the buttons along the same horizontal line generate the same tone. Here’s a chart that shows how the individual tones are laid out:
You can reproduce these individual tones yourself by pressing two buttons in the same column…
…or by pressing two buttons along the same row….
This will be the method we will use for setting the proper tones on your phone.
So let’s take your phone off the wall, or unplug it from the socket and begin the repair
Step one is to remove the cover from the phone. On this wall phone, there are two screws under the plastic label. Use a flat screwdriver to pop the plastic label cover off, and then use the same screwdriver to loosen the screws.
Lift the button pad off the mount, and lay it aside with the wires facing back towards the phone. At this point, you will notice two black cans on the back of the button pad. These are what we will adjust. The one on the left is for rows, and the one on the the right is for columns
Now, at this point you will need to power your phone so we can measure the tones that your phone is putting out. You can do this in a number of ways. You could plug your phone back into the wall socket, but you may end up dialing numbers you don’t want to actually call, so I just power the phone off an ordinary 9 volt battery (the phone company typically powers phones off of 5-6 volts)
If you have a desk phone, you can simply take a scrap telephone cord, cut one end off, and attach a 9-volt battery clip to the bare wires. The red goes to the + terminal, and the green to the – terminal on the battery. For a wall phone, it’s a little more complicated, but not terribly hard. On this wall phone, you see a screw terminal strip directly under the pushbutton pad. On the bottom left row of screws is a green wire. Connect this screw using your clip leads to the – side of your 9 volt battery. Just to the right of that on the second screw terminals, you see a red wire attached to the top, screw second from the left. Attach the + side of your 9 volt battery to this terminal with the clip leads
Now, it’s time to measure the frequency. Connect your multi-meter up to the same terminals that you connected the 9 volt battery, and set the mode to frequency. Now, remember up top how to make a single frequency? Press two buttons in a row, or two buttons in a column. Check the frequency the meter is displaying and adjust the controls on the back of the keypad to match the frequency. When you adjust the frequency, you will adjust all the tones in every row, and when you adjust the columns, you will adjust all the columns.
Another alternative you can do is to connect the old phone up to a land line, and then call the land line the phone is connected to with a cellular smartphone. There are several smartphone apps you can use that will decode touch tones. You can use one of those apps to listen to the touchtones as they are pressed and determine which one, and how far they are off. This is a bit harder to do however, as you cannot tell if it’s a row or column that’s off.
Once you have the tones as close as possible to what they need to be, go ahead, mount it on the wall, and make a call and test it out. Tell the person on the other end of the line that you are using a 40 year old phone!