UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Telephony and Telecomms

Notices

Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

Closed Thread
 
Thread Tools
Old 26th Aug 2014, 2:05 pm   #1
Compo69
Retired Dormant Member
 
Join Date: Aug 2014
Location: Basingstoke, Hampshire, UK.
Posts: 15
Default Mini Exchange to Contact Closure?

Hi
I convert vintage phones to play audio clips when the receiver is lifted or sometimes when dial or push-button can trigger a sound. We fit small sound players inside most of the time.

However: I hate having to strip out the insides of really nice old vintage phones and am also looking for a way to improve things.

To that end I was wondering whether it might be possible to build some kind of mini exchange that could Accept tone (or pulse as we can convert) dialling from a normal phone using a sequence of numbers, as would normally happen, but to then rather than making a connection to another phone on the same line be able to activate a simple contact closure? (to trigger my little sound player).
i.e If I dialled a pre-determined number it would trigger that particular contact closure.
I could therefore, hopefully, have a list of number sequences, as a normal phone would have phone numbers to ring, that I could in effect dial up a different sound clip for each.
The sequence need only be 3 numbers for example if that would make things any easier?

So having fumbled through that crude explanation above..... has anyone got any advice? Tips, Circuit diagrams, etc etc they could offer?
I would be most grateful!

p.s. I am in no way technical, but I know a man who is so careful with the technical questions, Thanks!
(+ apologies for any bad grammar or spelling mistakes above)
Compo69 is offline  
Old 27th Aug 2014, 12:29 am   #2
jjwayle
Tetrode
 
Join Date: Jun 2009
Location: Bromley, London, UK.
Posts: 66
Default Re: Mini Exchange to Contact Closure?

Ive dabbled in doing this and cobbled together a couple of circuits for one off projects.

If you just want a sound message played when the phone handset is lifted then supply the phone via a low voltage (clean) PSU, at say 12 volts and insert into the circuit a relay with 2 coils, the standard GPO was a relay with 200+200 ohm coils. When the phone goes off hook the relay is activated and the contacts can trigger a sound module. You can connect this to the line via an audio isolation transformer or if the relay has and extra tone winding (usually about 570 ohms) then you can inject it there and by transformer action the sound will be induced equally into the other two 200 ohm coils and down the line, all audio being balanced.

Another method is connecting via as you say a mini exchange. A BT revelation for example is ideal as it works with both tone and pulse dial phones. On different extensions you can make a small circuit that looks for the ringing then loops the line while starting and connecting to an audio module. I used this on a my Strowger exchange so dialling the old number 160 connects to a Dial-A-Disc recording. Another similar unit one 123 and 952 connects to a speaking clock reproduction.

Short video demo here (not the best, i need to get round to filming on my proper video camera!) https://www.youtube.com/watch?v=rpaD...8EAZGqF2Cry-zg

Hope that gives you some food for thought!

Jason
jjwayle is offline  
Old 27th Aug 2014, 11:07 am   #3
arjoll
Dekatron
 
arjoll's Avatar
 
Join Date: May 2006
Location: Invercargill, New Zealand
Posts: 3,440
Default Re: Mini Exchange to Contact Closure?

Asterisk and an FXS card?
arjoll is offline  
Old 27th Aug 2014, 1:17 pm   #4
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
Default Re: Mini Exchange to Contact Closure?



I'm reasonably technical, though not telephonically so and that means nothing to me......
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline  
Old 27th Aug 2014, 2:53 pm   #5
julie_m
Dekatron
 
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
Default Re: Mini Exchange to Contact Closure?

What ARJoll said.

You just need a scrap PC (anything 1 GHz or faster will do) and an FXO / FXS card (standard ones accept up to 4 modules, each of which can be FXO to talk to an exchange or FXO to ring a telephone). Install the Free and Open Source Asterisk software, and you have a fully-functional PABX! The FXS modules also accept pulse dialling and support a REN of up to 4 -- so they should be perfectly fine with old telephones (certainly I have had no problems with a GPO 746).

A TDM400P card fitted with one FXO and three FXS modules will allow you to connect three extensions and an exchange line. You can configure how the extensions behave; even going so far as to do things like dialling an "old" 3-digit number on one of the extensions calls the "modern" 6-digit number -- your own imagination is the limit. You can also run an application on the computer when extensions are dialled.
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments.
julie_m is offline  
Old 29th Aug 2014, 10:52 am   #6
Pellseinydd
Heptode
 
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
Default Re: Mini Exchange to Contact Closure?

Another simpler option is to have a phone or two hosted off an Asterisk PBX and get them to host the recordings. I have such a system with a variety of recording from old recordings from the 1800's through to the Goons Show. I get plenty of calls into the system to listen to recordings - for instance, last night I had five calls from visitors to MOTAT (Museum of Transport & Technology) in New Zealand calling to listen to an old recording of the Queen opening the Commonwealth cable to New Zealand in the early 1960's. And all the calls are free!

PM me as I'm sure I can help and you need little technical knowledge - which we can help you with.
Pellseinydd is offline  
Old 29th Aug 2014, 2:20 pm   #7
Compo69
Retired Dormant Member
 
Join Date: Aug 2014
Location: Basingstoke, Hampshire, UK.
Posts: 15
Default Re: Mini Exchange to Contact Closure?

Thanks everyone some food for thought.

However I could really do with a stand alone unit that can fit into a box! (and more reliable than a PC!)
Not really happy running via a PC as wouldn't that involve "booting the thing up" every day and launching whatever program was being used?
It needs to be more lake a static exchange, something like an office system?
On that thought wouldn't a simple system that a small office might use for internal calls do the job with something at the end to convert the call to ring into a contact closure?
Compo69 is offline  
Old 30th Aug 2014, 8:05 pm   #8
Compo69
Retired Dormant Member
 
Join Date: Aug 2014
Location: Basingstoke, Hampshire, UK.
Posts: 15
Default Re: Mini Exchange to Contact Closure?

Someone sent me this recently:
http://www.aholme.co.uk/Exchange/Design.htm

Looks like it might do the job?
Compo69 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 4:29 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.