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and very rarely ever needs repairs, once you fix them." - Dan/Panther

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Building small exchange

Started by dc4code, October 23, 2018, 08:00:15 PM

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As some of you know NPSTN (Alternative to C*NET) Is working well now It is now a peer to peer system like C*NET (the only difference between NPSTN and C*NET right now is the protocol we use for route table lookups. C*NET Uses eNum and we use HTTP)

NPSTN has a lot of exchanges across the world hosted by the community. It is also soon going to be fully open sourced.

I have some people that may send me some Electromechanical switches and my idea for this is I may create a Tandem for NPSTN that people can enter a dial-around-code to access and get dial-tone from the electromechanical switch, which, in turn, would contact to an Asterisk PBX and loop back to the NPSTN Network. so in other words. you can access the whole network from an electromechanical tandem office.

Now *IF* the person decides to send me the switch it will only be a Connector and possibly a selector. so still not enough to do what I need

I did, however, find this post on the forum ( )

This looks more like it! Relays are cheap from eBay direct from China... I already have a 48V 5A Power Supply and I have all the tools I need.

But the only thing is I am good with electronics like I can put stuff together and understand it... But I cannot read circuit diagrams at least not on this scale...

Can somebody please help me? Like a list of all the parts I need and then I could maybe get somebody to video chat with me while I set stuff up?

I know that might be asking a lot but I really need help with this!

Also if anybody wants to be apart of the NPSTN Network we can host a number for you on my exchange or you can actually host yourself using your asterisk server if you have one. It's just like C*NET but A little smaller (only like 11 members) and cooler. :)

We have a *simulated* WeCo SxS & #3XB on the network.

The website is (we got a new domain for it now)

So far we have:

Office code 222X hosted by Andrew Green in Canada
Office code 543X hosted by Teleplay in the UK
Office code 544X hosted by Teleplay in the UK
Office code 330-0 330-1 330-2 hosted by Hyland & Dylan in the US
Office code 264X hosted by Emil Engler in Germany
Office code 327X hosted by Dylan Cruz in the US
Office code 501-4 hosted by Anon User in the US
Office code 252X hosted by Dylan Cruz in the US

& more just can't remember it.

We have 3 operators once you dial 0 on the network and they will answer with 'Operator, number please?"
and they can route calls on the network, with this new system that exchange owners put on the asterisk server they can also do Busy Line Verify/Interrupt service!


Also, I understand that this system has no ringback signal or anything so I would like to have one

also, could I use these for anything?


Maybe to create a dial-tone or something?


Still wanting to put this together :)


The miniature 10 line exchange as per the Wireless World Aug 1980 article does not cater for connection to the outside world - it is simply an internal exchange much like an intercom which uses dial phones as stations.

Since it doesn't cater for connection to an outside line it cannot be used with C*NET or NPSTN.

Some years ago I found a website which described a "Home PBX with 9 internal lines and 1 external line" by a Dale Thompson. This website no longer exists but I did copy the description and the schematics to my PC. I think this might be a candidate for what you are looking for. I might add that the design was realised using wire-wrap techniques.

Western Bell

Is this it? Found googling "Home PBX with Nine Internal Lines and One Outside Line"


Quote from: Western Bell on January 08, 2020, 06:09:30 AM
Is this it? Found googling "Home PBX with Nine Internal Lines and One Outside Line"

That's the one... Funny, but I don't get this link in any of my Google results using the same (or any other) search criteria.

PS. I was using Startpage (not Google) and it doesn't return the link in search results. When I switched over to Google it does return the link.

Edit Jan 9.
Neither Bing nor Startpage will find the url in question. However, Google does return the correct result on the first page.


My last dugout in the basement is my first DIY cord-board.  As a student with a weird (or wired) hobby I made this of parts.

The simplest but reliable field exchange ever made? Just as on the German wwii field exchange I had to have an operators field telephone, but I made it more advanced. A holding coil for one trunk-line,  and bilt in buzzer. :-)

If you could need this or for parts, tell me but quicly :-)
I'm tiding up the basement.  :o

PS the felt-pen is only there as a size reference  ;)   DS