From web research, I discovered it's a Western Electric 211 Telephone (their "Spacesaver" model). Typically you'll see these with dials mounted on top of the metal box (they actually look pretty cool). This one is sans dial, making it a "manual" (rather than "dial") telephone.
This set consists of a G1 case and an F1 handset. When I opened it up I discovered that the case only contains a hookswitch and nothing else! The drawing below shows a "generic" 211's circuitry (the simpler wiring of my "no dialer" telephone is shown in yellow). Note that the circuitry at the left is contained in a separate "subset" unit (which I will discuss further, below).
As I mentioned above, these telephones are meant to be used with an external "Subset" (such as the Western Electric 634 or 684), which contains a network for the anti-sidetone circuit as well as the ringer bell.
To test the telephone without a subset, I simply connected one side of the phone line to the "GN" terminal, and the other side of the phone line to the "Y" terminal. This will place the hookswitch, the mic element, and the receiver element all in series and connected to the Telco line. This implementation is shown in the photo below.
But there are several drawbacks when wiring the set this way. First, there's no anti-sidetone circuit, so you'll sound fairly loud to yourself in the receiver when you're talking into the mic. Also, there's a DC voltage across the receiver element, and thus there's the possibility (allegedly) that, over time, this might demagnetize it. Finally, there's no suppression of "clicks" in the receiver when going On or Off hook -- if you're holding the handset to your ear while "flashing" the telephone hookswitch, you'll hear VERY loud clicks.
So it seemed that the thing to do would be to find an appropriate subset. I looked around for one, such as the 634A, 684, or the 685A, but all the ones I found were fairly expensive, and I really didn't want to spend a lot of money on one.
Hmmm...could I build my own?
Well, I didn't need a ringer because I have a phone with a ringer across the room on my desk. I really only needed a network. If I could find a network, I could build my own subset...
One network I found was a "101A" network that was used in telephones such as the Western Electric 302 . This is just a transformer, and it requires an additional 2 uF cap to work with the telephone. But the 101A is a bit primitive -- it doesn't include any components to limit clicks. I decided instead to use a more modern network such as the 4228 or the 425 (the 4228 is found in Princess phones (I believe), while the 425 (e.g. 425E) is found in the 685A subset and 500-series telephones) . In the end I purchased a 4228 network from someone I found via the "Telephone Collectors International" List Server (on Yahoo).
Here's how I connected my 211 to my external 4228 network:
I want to stress, these connections are only for my "no-dial" 211 set! Here's a list of instructions for making these connections:
Required:
- 4228 (or 425) network
- 5-wire cable
- 211 (sans dial) Telephone
Instructions:
- At the 211 Telephone, move the Handset's BLACK wire from the "BK" terminal to one of the two unused terminals marked "B".
- Using the 5-wire cable, connect one end of one of its wires to the "L2" terminal on the 4228 network, and connect the other end of this same wire to the "Y" terminal in the 211.
- Using the 5-wire cable, connect one end of one of its wires to the "GN" terminal on the 4228 network, and connect the other end of this same wire to the "GN" terminal in the 211.
- Using the 5-wire cable, connect one end of one of its wires to the "B" terminal on the 4228 network, and connect the other end of this same wire to the "B" terminal in the 211.
- Using the 5-wire cable, connect one end of one of its wires to the "C" terminal on the 4228 network, and connect the other end of this same wire to the "BK" terminal in the 211.
- Using the 5-wire cable, connect one end of its last wire to the "R" terminal on the 4228 network, and connect the other end of this same wire to the "R" terminal in the 211.
- Connect one of the two Telco wires to the "RR" terminal on the 4228 network.
- Connect the other Telco wire to the "L2" terminal on the 4228 network.
Here's a picture of my homebrew "subset" with the 4228 stuck to the bottom of a project-box with hot-melt glue. Telco comes in via an RJ connector on the left side. The gray wire bundle (5 wires) goes to the 211 set...
(There's a drawing HERE to help you identify the terminals on a 4228 Network. Note that "L2" is a dummy terminal (that is, it isn't connected to anything), and you can use its two screws to connect one side of the telco tip/ring pair to the telephone, as I've done.)
Here's the phone, mounted for use by the workbench!
Addendum, 2 August 2014:
Someone reported that they'd had a problem when applying these mods to a 211 telephone with dial, and that their phone would not dial.
The mods above are only for a 211 without dial. Do not apply them to a 211 with dial.
To adapt a 4228 network to a 211 with dial, I believe the required changes will result in wiring that looks something like this:
(Click on image to enlarge)
Please note the following, per the drawing above:
1. Assuming that the 211 has a 5H dial, the wire between the R terminal of the dial and the R terminal on the Hook-switch assembly should be removed (I believe this is a Red wire).
2. The wire from the BK screw terminal on the dial should no longer terminate at the B screw terminal on the Hook-switch assembly. Instead, you will need to connect the dial's BK terminal to the 4228 network (connection is shown above to the C terminal of the 4228).
Note that if you have a G7 body, you should be able to use the BL screw terminal on the Hook-switch assembly for this connection.
3. Therefore, you will need 5 wires to interconnect the 211 with your new subset (i.e. 4228 network plus Line-In signals), rather than the previous 4.
For reference, you can find a drawing of the original wiring of the 211, with dial, here (note that it doesn't include the 61M filter): http://www.classicrotaryphones.com/forum/index.php?topic=2111.0
(Also see Reference 2 in the Resource section, below).
Important note: I do not have a 211 with dial, so I cannot test this circuit. There might be a mistake. If you do try it, please let me know your results.
Resources:
1. Information on the 211 (and other old Western Electric phones) HERE.
2. Wiring & other info for the 211 (towards the middle of the post) HERE.
3. A source for old phones and parts (and subsets!) HERE.
4. 4228 Network information HERE and HERE.
5. "Telephone Collectors International" webpage and list-server.
Standard Caveat:
And of course, there's the standard caveat! I may have made a mistake, so use at your own risk!
OK, but the mounting bracket should be flipped so that it and the wall mounting screws are hidden behind the telephone. Would look much neater.
ReplyDeleteThanks for the article. Someday I'd like to try this if I can find a decent 211.
ReplyDelete73 de K0UC
tnx
ReplyDelete