Wow, I hear crickets on this sight... :(
Was there a mass funeral I did not hear about??
Any way, this is what I did over the weekend.
I needed to get this555 cord set workin, so I can test/link my CB phones together.
Finally, with Trainmans help, I got it working and now have to house it.
The Station sockets needed a permanent home, so I boxed them up, and added quick connectors to my power supply.
They work, but when I built them, I went point to point with the connections.
What I have, is a temp short on the power supply when stuffin a plug into a jack.
The supply eats it, and starts right back up, so all is working.
I would like to eliminate the temp short when plugging, but it will take more time, and re designing the station jacks. A work in progress!
Has anyone ever delt with the station jacks directly?
I would like to know the order of switch activation, which jack switch opens/closes first? second? So I can make this right.
I know thats all it is, it will come!
The jacks use a 3 pole 2 throw 24v relay to make the changes.
Not a lot of people here have intimate detailed knowledge about the switchboards circuits, myself included. This is probably why you have not had a lot of replies to these technical inquiries, I am sure you will get them as the experts check in.
Yeah, I have gathered that... :)
Myself, I have extensive knowledge if component level work.
8 years at TRW doin reverse engineering to make schematics for products we worked on.
I know I will resolve the issues, just need to see one. or maybe, if I can find a description with pics of the Station jacks, that will show me what I need to do. :D
A lot more collectors with switching expertise spend more time on the TCI Listserv.
You might find some reference documentation, including CDs and SDs, by searching in the TCI Library.
http://www.telephonecollectors.info (http://www.telephonecollectors.info)
Thanks Paul! I think I have most of whats available in the lib. been downloading bunches.
and always lookin for more.
http://www.telephonecollectors.info/index.php/browse/bsps/by-division-number/doc_details/6241-032-511-107-i1
Jack number 275 is what was used in the 555 switchboard station line circuit.
Thank you Trainman, again!!!
a couple clicks, and there it is.
THAT is why I shop here :D
Happy Friday!
Switchcraft 280 jack is close, but still not exact. Switchcraft 280 is is the same as WECO 280.
i have a feeling you might need to take parts of a few jacks and amke your own
Another thing I noticed when tracing out qires on one of my 555 cord units today. Pin 9 on the plug would be connected to frame ground. A couple circuits from both the CS and T relays end up at frame ground via Pin 9 through the switchboard wiring harness to frame ground.
8) I have never touched a CB board, but if I should make myselves a simple one with just lamps or LED's as signals and as simple as possible I would have started with this sketch. Probably used an old laptop power instead of a battery.
Of-course the coils could be relays with contacts for audible signals... but simple is a great start.
So the jack has one contact with a lamp to negative, and this will disconnect when the plug is in. The Ring is connected to ground (+) over a coil (or relay). When going off hook the lamps lit.
When plugging in the answer cord, the lamp is disconnected but the line is fed via the relay R and the operator may speak to you by operating a switch to operators telephone. (I would probably used an LB circuit as operators phone, and a capacitor in series.)
The caller asks for a number, the operator plugs in the ring plug and operates the magneto generator, waits for answer and disconnect the operators phone.
When bot ends hangs up, the relay releases, and the lamp on the cord-set lights up. when both cords are unplugged the lamp gets dark.
dsk
Thanks Trainman, for the switch info.
And thanks dsk, for the schematic.
I like it when I have options.
I will try this, and see what happens...
To pick the components may be tricky, The relay shold operate before 35 milliamps and resist a short of the line without burning out.
A laptop power gives about 18V we could calculate a telephone to have load like a 200 ohms resistor, so 2 telephones will be 100 ohms load. Then the relay should be a typical 12V relay but it will need to have a resistance of 200 ohms to operate OK. If we say 20 ohms on each line you only have about 100 ohms to each coil on the ring side of each jack.
Not sure, but I guess a 12V 2W (car) instrument lamp will do the job and glow pretty weak when you go off hook, but still survive dialing. Maybe a x-mas tree bulb will do it better? You have to try it out.
dsk
I took a peek inside my station line jacks. It looks like the tip and ring springs are just about the same length. It sure isnt set up like most of the jacks where tip makes first, and then. Ring.
The 275 jack looks like tip and ring almost make contact at the same time.
Yeah, seems like most all are about the same.
My setup, allows the tip to connect with ring upon plugging in, which shorts the power supply.
it recovers quickly, and works, but I would prefer it did not short out at first.
I wonder how the boards got passed that little ditty?
I do not really know, but it may have been so to just give a relay a pulse when you put in the plug. The power was never direct to the plug/jack but via some indicator or coil of some type. Full power to the line could harm the equipment.
dsk
Because the station line is getting its battery feed from pne source. This is the loop current flowing when you take extension phone off hook. When you plug in, you are switching the power from the first source flowing and switching in the power being fed from the cord circuit. I suspect the station jack is constructed the way it is, to switch so its a seamlesss switchover with no shorts
I think you are right. it must be designed "short free".
I just can't see how it was done. The jacks appear to be almost the same, " the t and r contacts".
So when the plug is inserted, the tip=negative, contacts the ring=positive, and SHORT.
I need to think it through, and redesign my station jacks so they don't cause a short. I can do that :D
Since I started with nothing, I can do what ever I want...
I looked at my jack setup last nite.
What I found, is the station jacks, are designed just like the 1/4" parts I am using,
The difference...is in the length of the "tip" on the plug.
In Both styles, the tip of the plug, will momentarily bridge the Tip to the Ring of the jack when plugged in.
The pbx plug, has a shorter Tip portion than the 1/4" plug, and does not bridge the T and R of the jack.
Thats how they did it. Now, I have to redesign my jacks to circumvent this issue.
I think I just got another wrinkle in my brain! lol
And when you get that puppy up and running, if/when I get a switchboard, I'll be picking your brains!
That may be a short trip Brinybay, lol, but happy to share :)
I have spent a great deal of time reverse engineering circuits because I did not have much/any information, just the item.
And then building mock ups to be able to test them.
That is where my strength is.
I always got the thing to work on thrown in my lap...but not the info.
Come in to work in the morning to find something new on my desk...what is it??? it is yours, ...make it work. ???
Yes, the Tip is shorter and cannot contact the T and R contacts at the same time.
Not like the 1/4" jacks, that short both momentarily.
I have reconstructed my station jack, see pic.
I now leave the jack dormant, until the relay locks on "manually", and switches power to the cord set.
It works slicker than puppy puick! no loud clicks, no shorts.!!! "short pause for a happy dance".
Gonna rewire the first two jacks this weekend to match the latest one, and that shud do it for this part of the project!
Last part will be the signal to the board for a requested call.