Info on Mechanical exchanges - UK Vintage Radio Repair and Restoration Discussion Forum

Sean Williams · 10th Dec 2006, 4:29 pm

Hi All,

Well, it had to happen eventually - I fancy a go at building a small(ish) exchange, so seeing as I know diddly about old exchange technology, I would like to gain more information!

Any suggestions as to the sort of literature I should be reading up on?

Offers of parts also gratefully recieved!

Cheers
Sean

Men in white coats are looming.......

jim_beacon · 10th Dec 2006, 4:42 pm

Sean,

the book(s) to look for, are the two volume set "Telephony" by Atkinson. They cover the full range of telephone signalling, switching, and power plant up to about 1960, and will give you all the basic information, and then add in the complex stuff (trunking etc.).

Your local library may have a set, but you can borrow mine if you get stuck.

Jim.

Sean Williams · 10th Dec 2006, 5:23 pm

Thanks Jim,

Found some on Abe books......

I feel a christmas present coming on!

Cheers
Sean

Denis G4DWC · 10th Dec 2006, 7:15 pm

I have a small mechanical Telephone exchange I built about 20 years ago when the XYL decided she wouldn't sit in the hall in front of a piece of hardboard loaded with jack sockets routing the Kids calls from their bedrooms to the playhouse, garage and my Shack.. Meany!!

It was based on a design in Wireless World dated August 1980 and used only miniature plug in relays to give 10 lines I think. I modified it to use a small Uniselector. It's been running 24/7 since I built it. Only problem it has is periodically losing audio across the transmission bridge due to dirty relay contacts. It really needs some DC wetting. I wasn't as dilligent then with the paperwork as I am now and only have a few dog eared bits of paper with scrappy drawings...Somewhere!!

Denis

Sean Williams · 10th Dec 2006, 7:19 pm

Hi Denis,

You seem to be faring better than I am.......

SWMBO has mentioned unspeakable things involving sharp objects when I showed a picture of a Strowger exchange.....

Still, feeling brave (and having a family already) I think I will continue in this quest!

Cheers
Sean

jim_beacon · 10th Dec 2006, 7:19 pm

Denis,

if you find the drawings, that sounds like an interesting little project.

Jim.

jim_beacon · 10th Dec 2006, 7:33 pm

Just a thought.....

Sean, one of those ex-SSR 5G relay / switching boxes might make a good basis for a simple relay type exchange - single digit dialling and the like (or 2 digit -strip the first digit unless it corresponds to an outside call.

It might even be possible to convert one of the register units, which will give you a small relay/uniselector exchange, in a a box about 2' x 2' x 1'. There were a lot of small PAX's (private auto exchange - not connected to the PO network) based on that technology, and of a similar size.

Jim.

AndiiT · 10th Dec 2006, 9:17 pm

It may be worth joining the Telecoms heritage group http://www.thg.org.uk/ as there is a wealth of information amongst it's members regarding all manners of telecoms equipment and exchanges

Regards

Andrew

BassoonBloke · 11th Dec 2006, 1:31 pm

Just spotted this thread.

Have a look at Beery's website. I know that he has been building a small mechanical exchange for a while, and it's fairly well documented on his website.

You may be able to PM him to get more info / help with this.

Alan.

ppppenguin · 11th Dec 2006, 2:01 pm

There must be a fair amount of old Strowger exchange kit in the hands of enthusiasts. I know at least one person who acquired signifcant amounts of Strowger kit when old PABXs were being scrapped. I can't imagine that there's any Strowger left in commercial service in the UK. I'm not counting installations such at the UAX at Amberley Museum which are maintained by enthusiasts.

The THG is surely the right place to find out more.

Sean Williams · 11th Dec 2006, 4:05 pm

ok, Have joined THG - Madness is getting closer - Now just need to add another Shed in the garden......

I think a recce of a few old sites in this area might be a good idea......

Cheers
Sean

ppppenguin · 11th Dec 2006, 5:00 pm

Sean, we're starting to get really worried about you. We often had our doubts but now you've become a moderator and joined the THG.

Sean Williams · 11th Dec 2006, 8:13 pm

Hmm, web trawling draws me to having a go at UAX12 - anyone got any more specific info, or sources of parts to play with?

Cheers
Sean

jim_beacon · 11th Dec 2006, 8:33 pm

Sean,

all the UAX series are described (with diagrams) in "Telephony".

Jim.

Sean Williams · 11th Dec 2006, 8:41 pm

Cool! - will be adding books to Xmas list!

Time for parts shopping......

Cheers
Sean

ppppenguin · 11th Dec 2006, 8:43 pm

Sean, when you come to collect the Tek manuals you are welcome to borrow my copies of Atkinson's Telephony until you find your own.

jim_beacon · 11th Dec 2006, 8:53 pm

I doubt that there is much UAX equipment left in the wild, but look out for small unkempt village exchange buildings on your travels (Telephony covers the standard buildings as well....). You may get lucky, as some of these buildings were either abandoned, or the equipment content reduced to a couple of wall mount boxes at the end of the Strowger era. I missed a UAX by about 3 weeks some years ago - the building was being converted, and the equipment went in the skip

Jim.

Sean Williams · 12th Dec 2006, 8:10 pm

Well, lots of usefull stuff about - My local library is getting Volume 2 of telephony for me - Vol 1 not available!

I think a small PABX might be the best way to start (well according to some expert nutcases!)

Have even found a likeminded individual here in Hitchin!

Cheers
Sean

jim_beacon · 12th Dec 2006, 9:21 pm

Quote:

Originally Posted by Sean Williams

I think a small PABX might be the best way to start (well according to some expert nutcases!)

Try a PAX, more common, and avoids the complication of external exchange lines

Jim.

Sam · 12th Dec 2006, 9:29 pm

Hi Sean, if you want I can photocopy the relavant pages on the UAX12 from Telephony. I think you sold me my copies anyway...

Sam

10th Dec 2006, 4:29 pm	#1
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Info on Mechanical exchanges Hi All, Well, it had to happen eventually - I fancy a go at building a small(ish) exchange, so seeing as I know diddly about old exchange technology, I would like to gain more information! Any suggestions as to the sort of literature I should be reading up on? Offers of parts also gratefully recieved! Cheers Sean Men in white coats are looming....... __________________ Engineers make things work and have spare bits when finished

10th Dec 2006, 4:42 pm	#2
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Info on Mechanical exchanges Sean, the book(s) to look for, are the two volume set "Telephony" by Atkinson. They cover the full range of telephone signalling, switching, and power plant up to about 1960, and will give you all the basic information, and then add in the complex stuff (trunking etc.). Your local library may have a set, but you can borrow mine if you get stuck. Jim.

10th Dec 2006, 5:23 pm	#3
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges Thanks Jim, Found some on Abe books...... I feel a christmas present coming on! Cheers Sean __________________ Engineers make things work and have spare bits when finished

10th Dec 2006, 7:15 pm	#4
Denis G4DWC Pentode Join Date: Oct 2006 Location: Brackley Northamptonshire, UK. Posts: 240	Re: Info on Mechanical exchanges I have a small mechanical Telephone exchange I built about 20 years ago when the XYL decided she wouldn't sit in the hall in front of a piece of hardboard loaded with jack sockets routing the Kids calls from their bedrooms to the playhouse, garage and my Shack.. Meany!! It was based on a design in Wireless World dated August 1980 and used only miniature plug in relays to give 10 lines I think. I modified it to use a small Uniselector. It's been running 24/7 since I built it. Only problem it has is periodically losing audio across the transmission bridge due to dirty relay contacts. It really needs some DC wetting. I wasn't as dilligent then with the paperwork as I am now and only have a few dog eared bits of paper with scrappy drawings...Somewhere!! Denis

10th Dec 2006, 7:19 pm	#5
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges Hi Denis, You seem to be faring better than I am....... SWMBO has mentioned unspeakable things involving sharp objects when I showed a picture of a Strowger exchange..... Still, feeling brave (and having a family already) I think I will continue in this quest! Cheers Sean __________________ Engineers make things work and have spare bits when finished

10th Dec 2006, 7:19 pm	#6
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Info on Mechanical exchanges Denis, if you find the drawings, that sounds like an interesting little project. Jim.

10th Dec 2006, 7:33 pm	#7
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Info on Mechanical exchanges Just a thought..... Sean, one of those ex-SSR 5G relay / switching boxes might make a good basis for a simple relay type exchange - single digit dialling and the like (or 2 digit -strip the first digit unless it corresponds to an outside call. It might even be possible to convert one of the register units, which will give you a small relay/uniselector exchange, in a a box about 2' x 2' x 1'. There were a lot of small PAX's (private auto exchange - not connected to the PO network) based on that technology, and of a similar size. Jim.

10th Dec 2006, 9:17 pm	#8
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Info on Mechanical exchanges It may be worth joining the Telecoms heritage group http://www.thg.org.uk/ as there is a wealth of information amongst it's members regarding all manners of telecoms equipment and exchanges Regards Andrew

11th Dec 2006, 1:31 pm	#9
BassoonBloke Pentode Join Date: Feb 2006 Location: East London, UK. Posts: 231	Re: Info on Mechanical exchanges Just spotted this thread. Have a look at Beery's website. I know that he has been building a small mechanical exchange for a while, and it's fairly well documented on his website. You may be able to PM him to get more info / help with this. Alan.

11th Dec 2006, 2:01 pm	#10
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Info on Mechanical exchanges There must be a fair amount of old Strowger exchange kit in the hands of enthusiasts. I know at least one person who acquired signifcant amounts of Strowger kit when old PABXs were being scrapped. I can't imagine that there's any Strowger left in commercial service in the UK. I'm not counting installations such at the UAX at Amberley Museum which are maintained by enthusiasts. The THG is surely the right place to find out more.

11th Dec 2006, 4:05 pm	#11
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges ok, Have joined THG - Madness is getting closer - Now just need to add another Shed in the garden...... I think a recce of a few old sites in this area might be a good idea...... Cheers Sean __________________ Engineers make things work and have spare bits when finished

11th Dec 2006, 5:00 pm	#12
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Info on Mechanical exchanges Sean, we're starting to get really worried about you. We often had our doubts but now you've become a moderator *and* joined the THG.

11th Dec 2006, 8:13 pm	#13
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges Hmm, web trawling draws me to having a go at UAX12 - anyone got any more specific info, or sources of parts to play with? Cheers Sean __________________ Engineers make things work and have spare bits when finished

11th Dec 2006, 8:33 pm	#14
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Info on Mechanical exchanges Sean, all the UAX series are described (with diagrams) in "Telephony". Jim.

11th Dec 2006, 8:41 pm	#15
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges Cool! - will be adding books to Xmas list! Time for parts shopping...... Cheers Sean __________________ Engineers make things work and have spare bits when finished

11th Dec 2006, 8:43 pm	#16
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Info on Mechanical exchanges Sean, when you come to collect the Tek manuals you are welcome to borrow my copies of Atkinson's Telephony until you find your own.

11th Dec 2006, 8:53 pm	#17
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Info on Mechanical exchanges I doubt that there is much UAX equipment left in the wild, but look out for small unkempt village exchange buildings on your travels (Telephony covers the standard buildings as well....). You may get lucky, as some of these buildings were either abandoned, or the equipment content reduced to a couple of wall mount boxes at the end of the Strowger era. I missed a UAX by about 3 weeks some years ago - the building was being converted, and the equipment went in the skip Jim.

12th Dec 2006, 8:10 pm	#18
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Info on Mechanical exchanges Well, lots of usefull stuff about - My local library is getting Volume 2 of telephony for me - Vol 1 not available! I think a small PABX might be the best way to start (well according to some expert nutcases!) Have even found a likeminded individual here in Hitchin! Cheers Sean __________________ Engineers make things work and have spare bits when finished

12th Dec 2006, 9:29 pm	#20
Sam Hexode Join Date: Apr 2003 Location: Higham-on-the-Hill, Leicestershire, UK. Posts: 338	Re: Info on Mechanical exchanges Hi Sean, if you want I can photocopy the relavant pages on the UAX12 from Telephony. I think you sold me my copies anyway... Sam __________________ Can he lead a Normal life, Doctor? No, he will be ... an Engineer.