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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

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Old 4th Dec 2011, 8:16 pm   #1
only1carra
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Default converted 746 GPO office Phone?

Hi
came across this today and just wondered if anyone could shed some light on what it is? Have had a look inside and dont fancy even trying to convert it!
Thanks
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Old 4th Dec 2011, 9:30 pm   #2
Darren-UK
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Default Re: converted 746 GPO office Phone?

It's just a once-common Switching Telephone, nothing unusual or rare. Scroll about one third down this page for more info.
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Old 4th Dec 2011, 9:58 pm   #3
Jim_746
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Default Re: converted 746 GPO office Phone?

If you do want to convert it take a look at this page and scroll about three quarters of the way down or use the find function of your web browser and look for planset.
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Old 4th Dec 2011, 10:56 pm   #4
DAVEHALL
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Default Re: converted 746 GPO office Phone?

Thought I'd replied to this post ,but my posts seem to have vanished .
Firstly - the tele is a 706 ,with a planset N625 ,to make it either a plan 105/107 .One was a main plus two extensions ( from memory restricted to internal) with DC signalling ,the other main plus one external extension with AC (17HZ),one leg earthed for signlling purposes.
Both used a PSU -(from memory 12v) ,the external extension one needed a convertor ringer .
Comon fault on these ws the transistor switch going O/C - the germnium transistors didn't like spikes .
If you google N DIAGRAMS -look for N806 FOR TELE .N1450/N1451 for Plan 105/107 and N625 for the base unit .
All this is from memory -last time I saw one of these was before I got married -some 40 years ago .
Source for N diagrms - http://www.samhallas.co.uk/repositor...rams/index.htm


Thought I'd replied to this post but my posts seem to have vanished.

Firstly - the telephone is a 706 with a planset N625, to make it either a plan 105/107. One was a main plus two extensions (from memory restricted to internal) with DC signalling and the other was main plus one external extension with AC (17HZ); one leg earthed for signalling purposes.

Both used a PSU (from memory 12V). The external extension one needed a converter ringer. A common fault on these was the transistor switch going O/C as the germanium transistors didn't like spikes.

If you Google "N DIAGRAMS", look for N806 FOR TELE. N1450/N1451 for Plan 105/107 and N625 for the base unit.

All this is from memory, the last time I saw one of these was before I got married some 40 years ago.

Source for N diagrams - http://www.samhallas.co.uk/repositor...rams/index.htm
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Old 4th Dec 2011, 11:48 pm   #5
AndiiT
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Default Re: converted 746 GPO office Phone?

Hi,
If the original block terminal is still present on the end of the instrument cord, you should be able to get this Planset to operate as a standard two - wire phone by connecting the White of your "modern" line cord to terminal 4 and the Red of the line cord to terminal 6. Wired in this way operating the 'SPK to EXCH' button should give you dial tone with the receiver lifted.

Whatever you do don't connect 10 Volt power supply to terminals 1 and 2 without ensuring that you have the correct polarity on them -ve to terminal 1 and +ve to terminal 2.

Some facilities such as exchange hold and the switch through to extension (both extensions are wired on terminals 14 and 16) will work without a power supply, the intercom circuit, buzzer and signalling lamps won't though.

If you want to advance and fit one or two extensions I have a wealth of knowledge (largely self taught through experimentation) on how to wire these up both the correct way and for use with more modern phones as the extension instruments.

Feel free to PM me.

Andrew
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Old 6th Dec 2011, 9:08 pm   #6
val33vo
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Default Re: converted 746 GPO office Phone?

As what has already been stated its what the GPO called a plan set, It is a telephone that would have typically been in an office where the main buisiness would have been done but with an external extension connected to it, so at night the ( subscriber ) could push a button on the front of it and transfer all the incoming calls to the external extension the other buttons allowed signalling between the main phone and external extension so the system could be used like an intercom if desired

The main problems with this type of telephone was the sliding contacts that lay beneath the push buttons and the stand alone transistor ringer

I well remember getting a right case of GBH in the right earhole when I was in the process of cleaning and lubricating them despite warning the subscriber his phone system would be out of order for 20 minutes or so, I had it in bits and the local buisiness man had an incoming call which he could not answer, ironically it eventually turned out to be a customer cancelling an order

( always look on the bright side of life )

regards

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Old 7th Dec 2011, 12:31 am   #7
OscarFoxtrot
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Default Re: converted 746 GPO office Phone?

Quote:
Originally Posted by val33vo View Post
I well remember getting a right case of GBH in the right earhole when I was in the process of cleaning and lubricating them despite warning the subscriber his phone system would be out of order for 20 minutes or so, I had it in bits and the local buisiness man had an incoming call which he could not answer, ironically it eventually turned out to be a customer cancelling an order
You could have lent him your Linesman's Tele.

Owain
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