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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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16th Feb 2021, 1:20 am | #1 |
Diode
Join Date: Feb 2021
Location: Newcastle on Tyne, Tyne and Wear, UK.
Posts: 4
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CB935 switchboard queries
Hi, I'm just about to take delivery of a CB935 2 + 4 switchboard.
I won't be using it as a switchboard (I don't know it is is fully working anyway). However, I would like to utilise some of the indicators etc in it in some way so need a little info please. I understand the board works on a 12v dc supply. I also know it has a generator to provide a ring to other lines. I'm guessing the generator is around 50v ac? In terms of the dolls eyes indicators what voltage do these run on? Are they powered by the 12v or 50v line? Do these indicators have 2 or 3 positions? Does the board have it's own buzzer or bell to sound or did it use an external bell? Thanks! |
16th Feb 2021, 11:03 am | #2 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,130
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Re: CB935 switchboard queries
The dolls' eyes (for the extensions) are operated from the 12V DC by detecting a loop when the extension goes off-hook (or goes back on-hook when the line is selected). The drop-down indicators for the exchange lines are operated by the incoming ringing current.
When a doll's eye operates it closes a contact to operate an internal buzzer.
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16th Feb 2021, 11:25 am | #3 |
Diode
Join Date: Feb 2021
Location: Newcastle on Tyne, Tyne and Wear, UK.
Posts: 4
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Re: CB935 switchboard queries
Thanks - that's really helpful. Cheers
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