Telephone 312 converting etc - UK Vintage Radio Repair and Restoration Discussion Forum

chipp1968 · 8th Feb 2009, 7:43 pm

I recently splashed out on a gadget that supposidly converts a rotary dial phone to work on tone dialing etc . so i dug out one of my old phones a 312 . at least thats whats on the base .It could be i swaped bses over many years ago though ! .
I tried out the phone as is ,and rememberd that on dialling there is a tinkle as the dial returns ,which shouldnt be .
I would like to fit the conversion to this phone . but first I would like to get it to proper woking order . It is probbly not wired corectly at the moment . It does have a modern mic fitted though .
Can anyone direct me to an easily understood way of doing this . and if any parts needed , where from? please
I have had a look already on the net , but am confused easily by the amount of stuff

Nickthedentist · 8th Feb 2009, 7:59 pm

Hi Chipp,

See here: http://www.britishtelephones.com/pstconv1.htm#332

It's for a 332, but a 312 is essentially the same but with added bits for party line working.

As for parts needed, you don't need anything except a 3.3K resistor to go in series with the bell. But if you don't have many other phones on the line, make do without it and link across instead.

Nick.

chipp1968 · 8th Feb 2009, 8:12 pm

Thanks Nick.
What about the Rectifier? mentioned on the site .
I have one other bell phone on the system and the other two phones are dect phones
ammendment .. i also have an old 30s phone with a buzzer instead of bell in service

Nickthedentist · 8th Feb 2009, 8:18 pm

The rectifier goes across the receiver (earpiece) to stop loud clicks when operating the hookswitch between calls etc.

See here: https://www.vintage-radio.net/forum/...tifier+element

Either steal one from a modern 700-series phone or leave it out. Or else they appear on eBay regularly enough.

Nick.

chipp1968 · 8th Feb 2009, 8:47 pm

Ok thanks Nick.Hopefully i should be able to sort this out soon

russell_w_b · 8th Feb 2009, 10:27 pm

Quote:

Originally Posted by Nickthedentist

The rectifier goes across the receiver (earpiece) to stop loud clicks when operating the hookswitch between calls etc.

Nick.

Isn't it just a couple of common or garden silicon diodes wired back-to-back to clip off above 600mV?

Nickthedentist · 8th Feb 2009, 10:55 pm

I think you're right, Russell, though I'm sure I tried this once with mixed results.

Nick

giraffenigel · 4th Mar 2009, 3:25 pm

All you need to make the rectifier are 2 DIODES(1N4001 or 1N4148)twisted together and wired between 5 & 6 in the telephone. Hope this helps

8th Feb 2009, 7:43 pm	#1
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Telephone 312 converting etc I recently splashed out on a gadget that supposidly converts a rotary dial phone to work on tone dialing etc . so i dug out one of my old phones a 312 . at least thats whats on the base .It could be i swaped bses over many years ago though ! . I tried out the phone as is ,and rememberd that on dialling there is a tinkle as the dial returns ,which shouldnt be . I would like to fit the conversion to this phone . but first I would like to get it to proper woking order . It is probbly not wired corectly at the moment . It does have a modern mic fitted though . Can anyone direct me to an easily understood way of doing this . and if any parts needed , where from? please I have had a look already on the net , but am confused easily by the amount of stuff

8th Feb 2009, 7:59 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,871	Re: Telephone 312 converting etc Hi Chipp, See here: http://www.britishtelephones.com/pstconv1.htm#332 It's for a 332, but a 312 is essentially the same but with added bits for party line working. As for parts needed, you don't need anything except a 3.3K resistor to go in series with the bell. But if you don't have many other phones on the line, make do without it and link across instead. Nick.

8th Feb 2009, 8:18 pm	#4
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,871	Re: Telephone 312 converting etc The rectifier goes across the receiver (earpiece) to stop loud clicks when operating the hookswitch between calls etc. See here: https://www.vintage-radio.net/forum/...tifier+element Either steal one from a modern 700-series phone or leave it out. Or else they appear on eBay regularly enough. Nick.

8th Feb 2009, 8:47 pm	#5
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: Telephone 312 converting etc Ok thanks Nick.Hopefully i should be able to sort this out soon

8th Feb 2009, 10:55 pm	#7
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,871	Re: Telephone 312 converting etc I think you're right, Russell, though I'm sure I tried this once with mixed results. Nick

8th Feb 2009, 8:12 pm	#3
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: Telephone 312 converting etc Thanks Nick. What about the Rectifier? mentioned on the site . I have one other bell phone on the system and the other two phones are dect phones ammendment .. i also have an old 30s phone with a buzzer instead of bell in service

4th Mar 2009, 3:25 pm	#8
giraffenigel Tetrode Join Date: Feb 2009 Location: Caernarfon, Gwynedd, UK. Posts: 51	Re: Telephone 312 converting etc All you need to make the rectifier are 2 DIODES(1N4001 or 1N4148)twisted together and wired between 5 & 6 in the telephone. Hope this helps