Telephone Rentals Loudspeaking Telephone

[JohnBHanson]

I have one of these and I wonder if anyone knows anything about it - as I cannot find anything about it on the web.
Ideally connection information, circuit diagram or indeed anything would be nice

[vosperd]

Hi,
I don't remember much about that particular set from my days at TR. The label on the keys indicate that it is part of a "secretarial" system. the secretary would have had a non loudspeaking phone and the bosses calls could have been diverted to her or answered directly and there would have been a direct intercomm between them. The TR loudspeaking phones would have had a wall mounted transistorised amplifier about a foot sqare and 3 or 4 inches deep.
I had to hand in all technical publications when I left so I don't know where you might find any info I'm afraid.
Don m5aky

[AC/HL]

Does it have any references marked, possibly a number with the prefix K.

[JohnBHanson]

No numbers or any lettering that I can see - nothing. It is connected to a connection box
by a long multicore cable. I think I have identified the power connections and the phone line connections, but not the bell circuit. I also don't know what voltage it would use and don't want to just try anything.

[JohnBHanson]

There is a handwritten number inside 536019. Does that mean anything?

[vosperd]

Are there any electronics inside either the junction box or the instrument?
It would be interesting to see more pictures.
Don

[JohnBHanson]

Electronics inside the instrument - I believe an amplifier although difficult to see. Inside the junction box lots of unlabeled connections (Not even connection numbers!) and some resistors that look like potential dividers of various forms.

[AC/HL]

I have an old Engineers handbook, but nothing resembles this instrument I'm afraid.

[AndiiT]

Hi,
This looks like the loud-speaking version of the 'Chief' end of a Plessey plan system which was designed to be used exclusively with a PAX. I have enclosed pictures of the equivalent telephone version including the circuit diagram and some marketing information for the non - loud-speaking version.

The chief's phone did not contain a bell - this was fitted in the "desk block" external to the telephone itself, the phone contained a rectifier and relay assembly to flash a lamp fitted to the chief and secretary's instruments to alert an incoming call when the intercom was in use.

Regards

Andrew

[Robsradio]

Originally Posted by vosperd

I don't remember much about that particular set from my days at TR.

Did you ever have dealings with TR clock systems too?

[vosperd]

Robsradio,
Hi, Just back from holiday and seen this posting. Yes indeed. Clocks PA systems and fire alarms etc. Still have a TMC masterclock clunking away every 30 sec on the wall in the kitchen.
Don.

[Robsradio]

Hi Don
That's good to hear.
I have a metal case TR and quite a few slaves from 1963, still runs a treat
But always kick myself for not taking a US Chronogram when offered one many years back!
Rob

[vosperd]

By the way the Instrument that was the subject of the thread I am told was known as a "Paxmaster 70". As I said I don't remember much about them myself but an ex colleague remembers them, he said he would get back to me if any info turned up.
TR were paranoid about getting all of their technical info back when anyone left so I have no info left. The pocket book did not go into much detail about the less well known stuff.
I had a few slaves at one time but none left now. I acquired a few of the wooden cased masterclocks as they were replaced by the later metal cased ones without the slave dial on the front. Only the one TMC left now but also have a Synchronome and a Magneta.
Don m5aky