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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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19th Feb 2016, 8:23 pm | #21 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,209
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Re: Old GPO Office Telephone
No, you connect the line to 4 and 6. (in the planset)
You connect the battery between 16 (-ve) and 20 (+ve) in the planset, although without extensions (and thus no line current in the extension circuit) I am not sure much will happen. You really need to download the diagrams I mentioned. N625 includes a layout of the planset, and shows how the termnals are numbered. |
19th Feb 2016, 10:00 pm | #22 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,127
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Re: Old GPO Office Telephone
It's OK, if all you want the battery to do is light up the red and white lamps, this works even without an extension connected. Also the main station happily connects to line without the extension. Beware, however, that the bell in the main unit will only ring on incoming with "speak to exch" selected. When "extn to exch" is selected, the bells are wired in series, so the absence of the extension and its bell means that the bell circuit would be open. This could be circumvented by bridging the connections for the extension's bell (terminals 11 and 14) - though I haven't actually tried it.
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19th Feb 2016, 10:12 pm | #23 |
Retired Dormant Member
Join Date: Feb 2016
Location: Coventry, West Midlands, UK.
Posts: 13
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Re: Old GPO Office Telephone
Thanks guys,
I'm on it right now |
20th Feb 2016, 2:51 am | #24 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: Old GPO Office Telephone
Terminal 11 - Terminal 14 would be a good place to fit the usual 3.3 kΩ resistor to decrease the REN of the old 1 kΩ bell.
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If I have seen further than others, it is because I was standing on a pile of failed experiments. |
20th Feb 2016, 9:33 am | #25 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,127
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Re: Old GPO Office Telephone
Bear in mind, though, that to get the benefit of this resistor, you need to keep the "extn to exch" button operated when the planset is on-hook. You would then need to press "speak to exch" on answer - returning to "extn to exch" when clearing the call.
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Mending is better than Ending (cf Brave New World by Aldous Huxley) |
21st Feb 2016, 5:15 am | #26 |
Retired Dormant Member
Join Date: Feb 2016
Location: Coventry, West Midlands, UK.
Posts: 13
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Re: Old GPO Office Telephone
It works - marvellous!
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21st Feb 2016, 5:17 am | #27 |
Retired Dormant Member
Join Date: Feb 2016
Location: Coventry, West Midlands, UK.
Posts: 13
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Re: Old GPO Office Telephone
And the other light!
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21st Feb 2016, 2:28 pm | #28 |
Octode
Join Date: Aug 2005
Location: Saltburn-East, Cleveland, UK.
Posts: 1,786
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Re: Old GPO Office Telephone
Hi,
Apart from having the added advantage of the lamps operating the "Speak to Extension Exchange Held" button should allow you to hold a call which is in progress, should you wish to - to be fair that feature should work whether there is a power supply connected to the plan set or not. Dave Moll mentioned about the bell not ringing if the speak to exchange key is not operated but I'm sure that the bell in my planset rang fine with all keys in the released position. I'll have to check the N diagrams when I get chance. An extension telephone could be connected on terminals 14 and 16 of the block terminal but you would have to have some additional bits (as already mentioned) for signalling between the extension phone and planset. Andrew |
21st Feb 2016, 3:40 pm | #29 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,127
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Re: Old GPO Office Telephone
I think it's only when "extn to exch" is pressed that the bell doesn't ring, owing to the bell in the extension being placed into circuit in series with the main in that position. Apologies if I didn't make that clear. This is my thinking about the resistor only being in circuit with this key pressed.
I must admit that I hadn't checked the "speak to extn" and "clear" states when I made the original comment.
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Mending is better than Ending (cf Brave New World by Aldous Huxley) |