710 chief phone with buttons
 

I picked up this phone and bell box the other day, it's nothing too exciting, but I thought it might be interesting.

Re: 746 chief phone with buttons
 

It is actually a 710 style rather than the later 746 style phone. Part of the Plessey range of phones for private systems or export - the 'main' station of a manager/secretary setup giving similar arrangements to the GPO's Plan 105/107. See https://britishtelephones.com/ericsson/n1906.htm for more about it.

Telephone Rentals bought most of their range of telephones and PAXes from Ericssons/Plessey and stuck their own labels on them.

Ian J
ex Plessey Communication Systems

Re: 710 chief phone with buttons
 

Hi, if the fourth (far most right hand) button is marked 'Trans Rlse' this particular model of phone and its associated extension was intended for use only with a PAX and was produced by Ericsson/Plessey and distributed by Telephone Rentals and (possibly) other private rental firms.

I had a brochure somewhere with details of a number of these systems, unfortunately I have mislaid it :(

Regards

Andrew

Re: 710 chief phone with buttons
 

I am intrigued to know what "Trans Rise" means.

Re: 710 chief phone with buttons
 

Oh, I think it's exciting.

Although from what I can make out, it's not actually GPO equipment and, as such not actually a 710, it seems to have the all-figured dial surround correct for the 706 and associated variants. From my limited experience, I would suggest these are not that common as most phones were upgraded to clear dials with numbered backing ring and a plain outer surround.

My green 706F was later upgraded to a 706F as above but would presumably have had a dial surround fairly similar to yours when it left the factory the first time around. Yours was never upgraded, so it's a reasonably interesting example of an all-figured dial surround.

From what I can gather there is a kind of all-figured dial surround that was issued later for the 747 and associated varieties, but the numbers are much larger. Practical, and not unattractive, but not contemporary.

Re: 710 chief phone with buttons
 

It actually says TRANS RLSE, four buttons, SECY, LINE, TRANS, TRANS RLSE.

Re: 710 chief phone with buttons
 

That certainly makes more sense, so they are respectively "secretary", "line", "transfer (call to other extension)" and "release transfer" - the equivalents on a planset 105/107 being "speak to extension", "speak to exchange", "extension to exchange" and "release".

Re: 710 chief phone with buttons
 

Although that would seem the case having one of these phones in my collection and doing some extensive examination of the circuit then wiring a "non standard" extension phone to it the buttons act as follows -

Secy is a latching button which connects the intercom battery/circuit and operates the buzzer in the secretary's instrument, the buzzer in that phone being silenced by an additional gravity switch when the handset is lifted.

Line (or Exch on the 740 version of this phone) does what it says on the tin and connects the Chief phone to, in this case, the PAX line.
I think that the strapping can also be arranged to disconnect the secretary's line access to prevent overhearing if desired.

Trans and Trans rlse are nothing more than a bell transfer switch, when the trans button is operated the bell circuit is disconnected in the chief instrument and "transfers" the bell circuit to an additional bell associated with the secretary's phone - The secretary phone had the option of two lines one exclusive and one shared with the chief.

There is a relay which operates a lamp on both phones to alert an incoming call at any time and particularly when an intercom call is in progress.

The trans rlse button is no more than a latch release for the transfer button

The diagram for the chief instrument can be found here and the secretary instrument here


Regards

Andrew

Re: 710 chief phone with buttons
 

I have it inside the bellbox.