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A youtube single slot controller

Started by Key2871, December 22, 2018, 09:15:48 PM

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I came across this a few years ago, and found it very interesting. With some research this is something that could be built for controlling a single slot phone.
Or even adapted to use for a three slot.
Some of the methods are to me a bit stone age and could be changed to work by other methods.
I have been wanting to do a simpler version for my single slot. Just have not really got anything going yet.

But this if just to give others ideas to explore in payphone coin relays.
Years back I had one that used 40 volts to control the coin relay. I just had to stretch the spring a tad for it to work.
And it did so flawlessly.

Dan F

All fine... I already made a controller that works with a "C" series ground start coin first phone. Also works with 3 slot phones. Working on refining it further.

Jim Stettler

Here is an article by Stan showing how to build a simple controller:
Jim S.
Text from article:
Unlike the first model, I'm not building these for sale or trade.  This design must be simple enough for any collector to build.

The new design has the following criteria.

1-    It must be as simple as possible to build.

2-    It must be as inexpensive as possible to build.

3-    It must be as small as possible so it will fit inside the payphone.

4-    It must be powered by tip and ring voltage.  No connection to the AC line.

5-    It must be built with parts that are readily available.

6-    It must make the payphone 'coin first'.  No dial tone until the initial deposit is made. Like in the 'good old days'.

7-    It will only return or collect the initial deposit.  One or the other, not both!  Your choice.

8-    To meet the first three criteria a coin must be deposited in order to answer an incoming call.  The coin will be treated like an initial deposit for an outgoing call when the phone is hung up.

9-    It must work with Western, Northern and Automatic Electric payphones as long as they have a single coil coin relay.

10-   If the payphone already has a single coil coin relay the only wiring changes will be the connections to the controller.

11-   Modification of the coin relay is OK, as long as its original appearance isn't changed.

12-    The main purpose of this controller is to animate the payphone's coin mechanism.  Really making the phone into - A PAY PHONE!               
You live, You learn,
You die, you forget it all.


Hi Jim Stettler,

thanks for sharing. I got some ideas.


Jim Stettler

Quote from: Key2871 on December 23, 2018, 04:48:27 PM
I remember that article well. But it was all the modification to the coin relay that I didn't like. So I just went with my own design. Also using the 48volt line power to operate the relay.
Only thing I did to insure operation was a plug a small blade flat screw driver in the center of the spring that aided the reset of the relay. Just a simple small twist to open the coil a little, and it worked like a charm. My out of pocket expense was a buck for the board fifty cents for the transistors used in the timer circuit. The other parts I got from scrap electronics including two dip relays. But I hadn't tried a timer chip as Stan did. But basically the same circuit. But I didn't have to modify the relay at all, every thing was the same original as installed. The circuit was just slightly larger to have room for the dip relays. It all fit right in the top next to the coin relay. Even with the upper removed, it was hardly noticeable.
I understand what you mean regarding the coin relay, I would buy a spare relay to modify if that was an issue in my application
The nice thing about this design is it is a complete design along with a parts list and board layout. The fact that Stan designed it to meet the stated objectives helps keep it easy.
There are several "free" controller circuit design that have been shared over the years. Most/all of these have included parts list and a breadboard or PC layout. There were a few kits offered as well.

Jim S.

Most seem to use a capacitor to "kick" the coin relay
You live, You learn,
You die, you forget it all.


It would not be 'VoIP' that has low-voltage it would be your ATA. Some are better then others,

I am currently selling a whole asterisk PBX and a good ATA for $35 you can see my thread about that in 'Classifieds'

This is not the BEST ATA I have but it does have High ring voltage and supports pulse dialing.

I do have an ATA that I can throw anything at it and it just works. That is the Cable Companies ATA/"EMTA"

It has 5 REN, Supports Pulse dialing, Works with all of my vintage telephone equipment, It's just an amazing ATA I love it! I just wish you could buy it standalone not locked to the Cable Companies Digital Landline service. But I do also have a GXW-4008 and a Cisco "Voice Gateway" That does everything the Cable Companies ATA is.

Basically, if you have an expensive ATA stuff is a lot easier.


Well I'm currently not spending money on c net anything.
I am aware that you are looking for people who have the desire to join your group, or what ever.
I'm not interested. Or I would have contacted you before.


I don't see any negative comments to your schematic. I was looking forward to seeing more on it. Sorry if you got some bad responses.
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"


I have been quietly reading this thread too. Was hoping to see photos as it progressed and see if it might work on a Bell phone in the UK.  :)
A collector of  'Monochrome Phones with Sepia Tones'   ...and a Duck!
Vintage Phones - 10% man made, 90% Tribble


Thanks. I am always interested in finding new things & learning about them.
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"


I will post updates : update, I just got closer to a CF DTF circuit tonight. So this is looking better everyday.
And the relay will not have to be modified to operate.
Hang in there it's getting closer now.


OK guys and gals, it came to me the other day, when I was back at my desk thinking about this control circuit that it's been a long time since I was doing mine. And a lot of dust was all over those memories of design and build. Well it also came to mind that some may be thinking that I am going to design a circuit board for my newest and most likely last circuit.
Because, like Stan became to realise, this is work, and a lot of it. So I am very close with finalizing my design, and on paper it's going to operate very much like Stan's high test model. But the thing is, you have to build it from scratch.
Yes, I will provide a schematic diagram for it, but that's all.
So for those who don't want to try it, run now. It really isn't that hard, but for those who don't do this,even for fun hobby they will not be very happy with it. And keep in mind to design a circuit board would be even worse, mostly for me.
I did it once before, when in the ATCA, I made and designed a circuit board for a network that would fit in the very top of the payphone, a three slot. This was back when I was brand new to these, and didn't know where to find the correct subset. So the terminal board in the back board was copied to make a network so you pick up the handset and talk or call out. Stan wanted me to make him twenty five of them, I said not likely because I was working full time and parts came from an ITT427 PC network, and removing parts from their board was hard enough, but to do twenty five? Yikes.
And this is before I made a control circuit to operate the relay, and other functions. Anyway, I'll provide a place to find the parts required, but you get to solder then to what's called a perf board, called that because it is, full of holes with copper spots on the back to solder components onto, then small wires have to be run to connect the dots so to speak.

So if this is not your cup of tea, sorry, this is the best I can do.
But keep this in mind, the circuit will not provide dial tone until a coin is deposited, that in turn starts a timer circuit.
Then after about 57 seconds, the collect turns on so when the receiver goes on hook, the coin is collected. If the handset is returned before the time is up for collect, it will return the coin. No modification is required to the coin relay.

When the phone remceves an incoming call, pick the handset up as the phone is ringing so you can talk. Just as it is with Stan's control, that others are making. The phone will not have to be changed at all. Only for phones with single coil relays though.
And can work with single slot sets as well, the only change is the relay, needs to be changed to a three slot coin relay.
This needs to be done so the contacts that are on those can operate the circuit.

So far I can't do anything about that otherwise.
But a hook switch contact may be needed for the circuit control, to operate the power to the circuit. I am still looking for another option to do this. Other than adding another switch to the hook switch to operate when the handset is removed or returned. If anyone has another way, please let me know. But other than those couple things, the phones stays the same. The circuit will provide the Power to operate the coin relay, collect or return. I'm still in the process of getting everything on paper and laid out in easy to understand terms. It may sound difficult, but if you're a hobbyist this would be considered moderate and not hard.
The circuit would fit in side any payphone, and quad wire using Red & Green wires for ring and tip, with yellow and black wires used for powering the circuit.
I'm on a tight financial situation, so I get parts as I can.
Any questions about this please ask. Thanks, Ken


Thanks Ken. I have no idea how to design a circuit so my hat's off to you. If it was easy we would not even be having this discussion, everyone would do it. I appreciate the effort. I have not done anything with a circuit board since I was in the Navy, approximately 40 years ago! I look forward to figuring out how it works and the challenge of building it. If there is anything I can do to help, just let me know. Thanks again!
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"

Stan S

I only have one question. Who are you?

For 40 years I owned an electronics manufacturing and design business. My main customer was Federal law enforcement.
I had a dark room and the ability to manufacture printed circuit boards from a taping to a drilled and populated board in 2 hours all done on my premises. Depending on how many employees I put to work I could have 25 of any board used as a telephone network built in a matter of minutes.

I have a feeling you are confusing me with a guy from California who sold 3-slots on Ebay. Mostly junk AEs!  He approached me to build networks for him. My answer to him was the same that I gave anyone who wanted me to do work for them. "The only products I sell are from my product line". I don't design or manufacture for anyone else and I only sell my products. I don't represent other manufacturers.

So once again I ask the question. Who are you?



Hey Harry, I just wanted everyone to know what is going on, and know my progress.

Stan, I have not had a conversation with you for years. Last one was thirty plus ago, about the controller I was offering in the club. I was a member for a long time. #2633 and the first time I heard from you was after my article about the network circuit I made for my NE 233 and you wanted to know if I would make some for you. I declined because I was working full time, but I did want to let others know what was needed, I even made trace drawings for it. After I made my own circuit board and etched it, drilled etc.
You told me about your controller, the first one in the tan box. I was talking to you about how I used a power supply that put out 45 VDC, and transistor circuit and relays to change the polarity on the coin relay. I didn't know that much about electronics, still don't. But I like tinkering and trying to make what I did, better. It's been a long time since I was doing that, and as mentioned, a lot of dust was on those memories.
I thought I could do some things, but I later realised it wouldn't work that way. But you were in NY, had your own electronics business, that's when you came into doing controllers and things like that. Long time, a lot of years past. I'm still tinkering because it helps keep boredom down.