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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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5th Jun 2019, 8:14 pm | #1 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
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Bell switch memories
When my parents moved into their new house in 1953 they had a telephone service installed immediately as my dad had a physiotherapy practice in the front room.
There was a tele 332 in the kitchen and a second 332 in their bedroom. There was a Bakelite tumbler switch screwed to the skirting board in the bedroom, wired into the connection box (BT20/4?) that turned off the bell This was presumably for my benefit, so I wouldn't be woken as a baby. When I was a schoolboy, I reverse engineered the phones, (didn't we all?), and I remember thinking it was quite cool that even though the series connected bell was shorted out by the switch, (which was just a normal mains on/off switch), the switch was mounted upside-down and the cover the right way round, so according to the legend printed on the cover, when it was "off" the switch contacts were closed. Was that the normal way of muting a 300 series bell? I can't remember seeing a similar switch used anywhere else.
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5th Jun 2019, 8:27 pm | #2 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
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Re: Bell switch memories
Yes, the way to disable a series bell was to short it out, as the circuit to any other bells needed to be maintained. Maybe what was unusual about yours was the use of a switch repurposed from non-telephone use that was marked "on" and "off". When converting old telephones with internal bell on/off switches from serial to parallel, it has been my experience that I have had to swap the open-when-on and the closed-when-on wires. Foruntately, they always seem to have been made as two-way switches.
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5th Jun 2019, 8:47 pm | #3 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
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Re: Bell switch memories
Thanks Dave, as it happens the electrician wiring those new houses became a lifelong friend of my dad. Perhaps he installed the switch as a naughty unofficial modification.
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5th Jun 2019, 9:02 pm | #4 |
Heptode
Join Date: Apr 2011
Location: Edinburgh, UK.
Posts: 805
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Re: Bell switch memories
I've seen one or two of those switches (possibly on Ebay). As most tumbler switches didn't have a legend, I assumed they were made for the GPO.
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5th Jun 2019, 9:13 pm | #5 |
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Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
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Re: Bell switch memories
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6th Jun 2019, 10:59 am | #6 |
Heptode
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
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Re: Bell switch memories
And if you hadn't a Tele 328 on the van, you'd fit a Tele 332 with a 'Switch Tumbler 1M' - it does appear on the N diagram for the Plan 1A - Extension telephone with 'Bell On/Off' switch - but usually used when the extension was a Tele 232.
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6th Jun 2019, 2:12 pm | #7 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
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Re: Bell switch memories
A 65 year old mystery solved, thanks to Ian
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