Author Topic: GPO Plug 420 line cables... (Read 2894 times)

twocvbloke · « **on:** December 12, 2012, 03:29:58 PM »

I forgot I bought these the other day, just after I got the Mk28 I think...

http://www.ebay.co.uk/itm/390492035742
http://www.ebay.co.uk/itm/271097313701

Anyway, got them mostly cos they were there, but mainly cos I wanted something a bit different for the Mk28, and the ivory one just cos I could...

I don't really know much about these, just that they have a Plug No. 420 on one end and the usual spades & grommet on the other, and they need a Jack No. 95A or 95B to connect to...

I think they were used as part of Extension Plan No. 4, which was essentially what we have today, just wired slightly differently and always had a bellset connected to the line, so you could have a few points round the house or business to which you could connect your phone to without having to have it re-wired by a GPO engineer...

But anyway, pictures, thought I'd do a size comparison of the 420s against a US 283B plug, a BT Plug 431, and an RJ11, and you can see the 420 is HUUUUGE in comparison to all three, I can understand why they dropped those in favour of the 431...

gpo706 · « **Reply #1 on:** December 12, 2012, 05:42:55 PM »

I needed to get one of these for my Trimline, then I had to find the socket to plug it into!

Thanks by the way for the heads up, just bought an Ivory 420 for the Trimline, which suits it fine till it plugs into the brown soapdish!

Nigel 777 etc is the bloke that used to do the repro Trimphone cords, but only in white.

twocvbloke · « **Reply #2 on:** December 13, 2012, 04:51:25 AM »

I'm confused now, by Trimline, do you mean the US phone, or the Geemarc copy of the Trimphone?

gpo706 · « **Reply #3 on:** December 13, 2012, 01:08:18 PM »

No, have an ivory Trimline, the US version with a 420 line!

twocvbloke · « **Reply #4 on:** December 13, 2012, 04:03:30 PM »

Sounds rather unusual then...

I'm not sure what to do with my Ivory 420 cable, I guess I'll just have to get another phone to go with it...

Owain · « **Reply #5 on:** December 13, 2012, 07:19:55 PM »

Jack Socket 95A

http://www.telephonesuk.co.uk/line_jacks.htm

The additional contacts are necesarry because in that system the bells were wired in series, so a contact was needed to link across the telephone bell terminals when the telephone plug was removed to preserve the series link to other phones. The telephones had to be wired differently depending on whether there were 1 or more than 1 telephones to be plugged in.

http://www.samhallas.co.uk/repository/n_diagrams/4000/N4506.pdf

twocvbloke · « **Reply #6 on:** December 14, 2012, 04:45:55 AM »

You know, it'd be interesting to wire up a Plan 4 system on one of the 616's extensions, as a demonstration of course, it's just finding the Jack 95s that would probably be the hardest part...

Owain · « **Reply #7 on:** December 14, 2012, 05:08:19 AM »

It would be even more interesting to do it with Telephones Special Range and an answering machine in the mix ....

twocvbloke · « **Reply #8 on:** December 14, 2012, 06:55:53 AM »

Nah, I don't really like the TSR range, too modern looking for my liking...

Owain · « **Reply #9 on:** October 08, 2013, 06:24:26 PM »

Quote from: twocvbloke on December 14, 2012, 04:45:55 AM

You know, it'd be interesting to wire up a Plan 4 system on one of the 616's extensions, as a demonstration of course, it's just finding the Jack 95s that would probably be the hardest part...

Here you go

http://www.ebay.co.uk/itm/171145203001

twocvbloke · « **Reply #10 on:** October 09, 2013, 02:29:18 AM »

I have two 95As now, the bit that truly is the hardest part is the correct extra switches (19B-1 or 36B-1, the latter replaces the former) that need fitting to use two phones on one Plan 4 system, and the problem with searching for a 36B is it turns up a lot of bras....

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