GPO 52A Terminal block to RJ11?? - UK Vintage Radio Repair and Restoration Discussion Forum

twocvbloke · 12th Apr 2011, 3:20 pm

Okay, I have been planning this for a little while now, and only just got round to it, it's basically taking a tried and tested, but rather inconvenient, GPO 52A BT and coupling it with the relatively modern RJ11 connector....

It took a fair bit of trimming of the plastic base to fit the socket, pulled out of a Binatone cordless phone base unit, I think, and one slight drawback is that it's 2-wire, not 3-wire, but I'm sure once I find a phone to attach this to that the wiring would not be too much of a problem to deal with...

AndiiT · 12th Apr 2011, 7:36 pm

Hi,
There were a few of the BT Relate series telephones which used RJ11 sockets and were 3 wire devices, some of the RJ11 sockets were used for handset cord connections which are four-wire.

If you can get hold of one of these phones as a donor unit it would serve as a source for four terminal RJ11 sockets - these may be PCB mount ones though.

Regards
Andrew

twocvbloke · 12th Apr 2011, 7:49 pm

Well, the thought I had was that as an old GPO phone, such as an unconverted 706 or 746, has 2 wires coming into the BT, the strap connects to the Ringer wire, and inside the phone lies the capacitors for it to act as it's own Master socket, so the RJ11 connector only really needs 2 wires, and the phone would at a guess not require a full conversion if I used it on a PABX, given how the ones I'm looking at only use 2 wires from CCU to Socket...

It was just one of those "Technical exercises", it kept me busy for an hour, I just need to find a matching black telephone to go with it...

twocvbloke · 12th Apr 2011, 7:50 pm

I just thought, I have that M3xxxn phone upstairs, that has a 4-way RJ11 socket, could have used that!!!

Ah well....

AndiiT · 12th Apr 2011, 11:03 pm

Quote:

Originally Posted by twocvbloke

... and inside the phone lies the capacitors...

Hi,
Be aware that some phones that have been through the GPO/BTs "clean up" process and converted to plug and socket working before leaving the refurbishment centre may have had the bell capacitors removed, this should only be relevant to the 746 and associated types (756/8 etc.) 706 types should always have a capacitor fitted.

Regards
Andrew

BGmidsUK · 12th Apr 2011, 11:08 pm

Old PC modem cards may be a good source of RJ11 sockets.

Brian

twocvbloke · 12th Apr 2011, 11:21 pm

I was thinking of unconverted phones, rather than de-converting converted phones, though I don't think it would be too hard to wire in some appropriate capacitors for such phones...

As for Dialup modems as a source of RJ11 sockets, yep, they would be, though I haven't seen one of them in over two years...

(infact, the last one I saw had suffered a direct lightning strike, charred computer parts are interesting to see!!! Couldn't save the computer though, lightning has a bad habit of cooking the BIOS chips)

Chipmunk · 23rd Apr 2011, 2:34 am

Ebay can be a good source of RJ12 sockets (RJ12 is an RJ11 with 4 contacts, RJ11 is just the centre 2 contacts, as used by most DSL modems and so forth).

If you specifically search for RJ12, you should find the 4 wire versions. Alternatively, maplin sell them as FCC68 connectors

If you want a good ready supply of dialup modems for parts, your local dump will usually sell you obsolete computers for a handful of small coins if you're nice.

If they ask more, they're taking the mickey!

12th Apr 2011, 3:20 pm	#1
twocvbloke Retired Dormant Member Join Date: Oct 2010 Location: Colne, Lancashire, UK. Posts: 527	GPO 52A Terminal block to RJ11?? Okay, I have been planning this for a little while now, and only just got round to it, it's basically taking a tried and tested, but rather inconvenient, GPO 52A BT and coupling it with the relatively modern RJ11 connector.... It took a fair bit of trimming of the plastic base to fit the socket, pulled out of a Binatone cordless phone base unit, I think, and one slight drawback is that it's 2-wire, not 3-wire, but I'm sure once I find a phone to attach this to that the wiring would not be too much of a problem to deal with... Attached Thumbnails

12th Apr 2011, 7:36 pm	#2
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: GPO 52A Terminal block to RJ11?? Hi, There were a few of the BT Relate series telephones which used RJ11 sockets and were 3 wire devices, some of the RJ11 sockets were used for handset cord connections which are four-wire. If you can get hold of one of these phones as a donor unit it would serve as a source for four terminal RJ11 sockets - these may be PCB mount ones though. Regards Andrew

12th Apr 2011, 7:49 pm	#3
twocvbloke Retired Dormant Member Join Date: Oct 2010 Location: Colne, Lancashire, UK. Posts: 527	Re: GPO 52A Terminal block to RJ11?? Well, the thought I had was that as an old GPO phone, such as an unconverted 706 or 746, has 2 wires coming into the BT, the strap connects to the Ringer wire, and inside the phone lies the capacitors for it to act as it's own Master socket, so the RJ11 connector only really needs 2 wires, and the phone would at a guess not require a full conversion if I used it on a PABX, given how the ones I'm looking at only use 2 wires from CCU to Socket... It was just one of those "Technical exercises", it kept me busy for an hour, I just need to find a matching black telephone to go with it...

12th Apr 2011, 7:50 pm	#4
twocvbloke Retired Dormant Member Join Date: Oct 2010 Location: Colne, Lancashire, UK. Posts: 527	Re: GPO 52A Terminal block to RJ11?? I just thought, I have that M3xxxn phone upstairs, that has a 4-way RJ11 socket, could have used that!!! Ah well....

12th Apr 2011, 11:08 pm	#6
BGmidsUK Retired Dormant Member Join Date: Oct 2007 Location: Leicester, UK. Posts: 809	Re: GPO 52A Terminal block to RJ11?? Old PC modem cards may be a good source of RJ11 sockets. Brian

12th Apr 2011, 11:21 pm	#7
twocvbloke Retired Dormant Member Join Date: Oct 2010 Location: Colne, Lancashire, UK. Posts: 527	Re: GPO 52A Terminal block to RJ11?? I was thinking of unconverted phones, rather than de-converting converted phones, though I don't think it would be too hard to wire in some appropriate capacitors for such phones... As for Dialup modems as a source of RJ11 sockets, yep, they would be, though I haven't seen one of them in over two years... (infact, the last one I saw had suffered a direct lightning strike, charred computer parts are interesting to see!!! Couldn't save the computer though, lightning has a bad habit of cooking the BIOS chips)

23rd Apr 2011, 2:34 am	#8
Chipmunk Triode Join Date: Mar 2007 Location: Southampton, Hampshire, UK. Posts: 30	Re: GPO 52A Terminal block to RJ11?? Ebay can be a good source of RJ12 sockets (RJ12 is an RJ11 with 4 contacts, RJ11 is just the centre 2 contacts, as used by most DSL modems and so forth). If you specifically search for RJ12, you should find the 4 wire versions. Alternatively, maplin sell them as FCC68 connectors If you want a good ready supply of dialup modems for parts, your local dump will usually sell you obsolete computers for a handful of small coins if you're nice. If they ask more, they're taking the mickey!