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Old 15th Jun 2019, 1:24 pm   #1
Otari5050
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Default 746 phone with extra buttons

I'm currently going through my store of vintage phones which have been packed away in boxes (I have 6 banana boxes of them!) for some 20 years now.
While checking them all out I found one with a recall button, and one with two push-buttons and a label I can't work out.

The left-hand button is marked SEC ' T and the right-hand is marked NORM (that one I can understand).
Anyone know what SEC ' T is?
This phone has an extra bell inside with its own single strike mechanism, an extra terminal strip, and a multi-contact switch assembly underneath the SEC ' T button.
The line cord has 6 wires - the usual red, green, white, blue plus an orange and a black.

While we're talking buttons, please remind me how the RECALL button worked. I know it's not the same as RE-DIAL.
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Old 15th Jun 2019, 2:24 pm   #2
Dave Moll
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Default Re: 746 phone with extra buttons

"SEC'T" is presumably short for "secret", the opposite being "normal". As to what exactly this means on this 'phone, it may be for use with a scrambler unit for transmitting speech in a manner that cannot be intercepted without the use of a second scrambler to decode it - enabled by pressing "SEC'T", while "NORM" would revert to sending speech in its normal, unscrambled form. Others may be able to correct me here or elucidate further.

Recall is a way of initiating additional functions (usually on a PBX) such as call transfer etc. When RECALL is pressed, dial tone is returned so that another extension or service can be dialled while the original caller is held. Exactly what functions can be used depend on what is provided by a particular PBX.

There are two types of recall: timed-break or earth recall. Again, which type is used depends on what PBX is in use. On the whole, earth recall is used on older systems and timed-break recall on more modern ones.

Presumably, unless the extras are a later modication, the actual model number may be something other than 746. Please can you confirm what is stamped on the base.
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Old 15th Jun 2019, 2:30 pm   #3
Pellseinydd
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Default Re: 746 phone with extra buttons

SEC'T = 'secret' . Probably used with a GPO/PO 'extension Plan 12A' which had two phones in parallel on the same line with the facility to 'switch' one of the phones off the line to afford secrecy for the other - plus the ability to call between each other. See https://britishtelephones.com/extnplan.htm under Plan 12 and 12A.

'Recall' was originally used on Private Manual Branch eXchanges to recall the operator. Flashing the switchhooks which was done on a call to a public manual exchange could not be used on a PMBX exchange line call as both operators would respond! On a Private Automatic Branch exchange, it was used on an outside call to return internal dialling tone so that the call could be transferred. On earlier PABXs, it used a system called 'earth recall' which needed a separate earth wire to each telephone but in the 1980's 'Timed Break Recall' (effectively the same as dialling '1' with a pulse dial) replaced 'earth recall' BT referred to 'timed break recall' as 'Register Recall' - hrence we have the Tone Dialling Telephone 782R with Earth Recall fitted and the Telephone 782RR with 'register recall' fitted (a separate PCB inside the phone). The Tele 782RR is a lot less common than the 782R.

Last edited by Pellseinydd; 15th Jun 2019 at 2:37 pm.
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Old 15th Jun 2019, 3:22 pm   #4
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Default Re: 746 phone with extra buttons

Just had a look through a lot of NZPO diagrams - I have scans of several thousand but there don't seem to be any of the NZPO telephones or extension plan arrangements. The NZPO often followed the UK General Post Office Telephones practice - I have some NZPO 'Engineering Instructions' which follow the numbering pattern and layout very similar to the UK GPO practice - you'd be hard pushed to spot the differences!

I would say that it was from a Plan 12A type set up rather than use with a scrambler - having maintained scramblers during my GPO days over here.
Incidentally the second internal bell is not a pattern I've seen in the UK.
GEC did have a factory in NZ where the 100 type phones were manufactured - all the NZ 100 type phones that I have on my NZPO PABXs were manufactured in NZ by GEC.
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Old 15th Jun 2019, 4:31 pm   #5
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Default Re: 746 phone with extra buttons

I would have thought "SEC T" was shortened version of secretary .
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Old 15th Jun 2019, 5:50 pm   #6
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Default Re: 746 phone with extra buttons

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I would have thought "SEC T" was shortened version of secretary .
That would be my first thought too - so that when already in a call, you could push the "Sec't" button and get your secretary to join the call to take notes/transcripts of the conversation - or alternatively to divert your calls to your secretary when you were busy/out-of-office.

We had something similar on the 74x-phones on the system where I worked in the early-80s: a "Forward" button linked to a call-group, so if you were out/did not want to be disturbed you pressed "Forward" and any calls to your number got routed to the call-group, which was made-up of your other team-members. In the pre-voicemail days this was better than having calls simply go unanswered.
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Old 15th Jun 2019, 6:09 pm   #7
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Default Re: 746 phone with extra buttons

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I would have thought "SEC T" was shortened version of secretary .
Not when used with 'Normal' - the 'raised comma' indicates there are other letters.

The Part Number is 20/PBU/372 for 'Sec't' is shown on page 2 of N diagram N849

And when you look at the diagram for Plan 12A N4514 - extension plan with secrecy - you'll find the 20/DBU/372 listed amongst the components to be used.

I can't think of any arrangement where the term Secretary' was used in Extension Plans. The Plan 5, 7 105 and 107 were often referred to as a 'manager/secretary' arrangement but the buttons/switches are refer to 'main' or 'extension'.
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Old 15th Jun 2019, 6:20 pm   #8
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Default Re: 746 phone with extra buttons

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Quote:
Originally Posted by qazxsw123 View Post
I would have thought "SEC T" was shortened version of secretary .
That would be my first thought too - so that when already in a call, you could push the "Sec't" button and get your secretary to join the call to take notes/transcripts of the conversation - or alternatively to divert your calls to your secretary when you were busy/out-of-office.

We had something similar on the 74x-phones on the system where I worked in the early-80s: a "Forward" button linked to a call-group, so if you were out/did not want to be disturbed you pressed "Forward" and any calls to your number got routed to the call-group, which was made-up of your other team-members. In the pre-voicemail days this was better than having calls simply go unanswered.
The 'forward' facility sounds very much like button on a featurephone as introduced on electronic systems of the early 1980's where call forwarding was one of the new features.

The PO/BT never had such a button on their 7XX range of telephones.

See N1248 for a picture of the Plan 12A telephone with a 'SEC'T' button for secrecy.

I always thought that 'secretary' ended with a 'y'
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Old 15th Jun 2019, 6:24 pm   #9
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Default Re: 746 phone with extra buttons

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Originally Posted by Pellseinydd View Post
Quote:
Originally Posted by qazxsw123 View Post
I would have thought "SEC T" was shortened version of secretary .
Not when used with 'Normal' - the 'raised comma' indicates there are other letters.
The "apostrophe' can represent one or more missing letters, eg Cox'n and it's.

Secretary would have been my guess too.
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Old 15th Jun 2019, 6:49 pm   #10
Pellseinydd
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Default Re: 746 phone with extra buttons

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Originally Posted by Scimitar View Post
Quote:
Originally Posted by Pellseinydd View Post
Quote:
Originally Posted by qazxsw123 View Post
I would have thought "SEC T" was shortened version of secretary .
Not when used with 'Normal' - the 'raised comma' indicates there are other letters.
The "apostrophe' can represent one or more missing letters, eg Cox'n and it's.

Secretary would have been my guess too.
How come that the PO only refer to the button used for plan numbers involved with secrecy ? They never mention secretary anywhere in their N diagrams
Surely secretary would have been SEC'Y ? I can find no reference to secretary in PO/BT extension plan arrangement. It is always Main or Exten

Where are any references to secretary in the GPO/PO/BT N diagrams ?
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Old 15th Jun 2019, 8:35 pm   #11
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Default Re: 746 phone with extra buttons

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Surely secretary would have been SEC'Y ?
Yes I can certainly see what you are getting at. As someone who knows little about such matters, I think it would be because a secretary would be in most offices. A secret line far less common so the former option would be the straw grasped.
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Old 15th Jun 2019, 9:50 pm   #12
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Default Re: 746 phone with extra buttons

Hi, whilst looking very much like a 746 this phone is most likely one end of a Plessey/Ericsson Plan system which were supplied on private rental to companies and were often used on PAX systems which didn't touch the public telephone network.

SEC'Y is indeed short for Secretary so this would have been the Manager end of the installation (often referred to as CHIEF by the phone supplier).
The additional contacts on the switches are for line/extension switching and this model looks like it may even contain a ringing generator.

I have a copy of a catalogue somewhere which may include your phone, feel free to PM me if you would like a copy to look at

Edit - I have just re read some of the comments and suspect that it may well be the equivalent of Plan 12A that Ian has posted a link to, the additional bell being contained in the phone rather than externally as shown on the N diagram.

Regards

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Last edited by AndiiT; 15th Jun 2019 at 9:56 pm.
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Old 15th Jun 2019, 10:09 pm   #13
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Default Re: 746 phone with extra buttons

Could the SEC'T be used as a cut off for the transmitter- the same as mute used today?
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Old 15th Jun 2019, 10:53 pm   #14
Pellseinydd
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Default Re: 746 phone with extra buttons

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Originally Posted by AndiiT View Post
Hi, whilst looking very much like a 746 this phone is most likely one end of a Plessey/Ericsson Plan system which were supplied on private rental to companies and were often used on PAX systems which didn't touch the public telephone network.

SEC'Y is indeed short for Secretary so this would have been the Manager end of the installation (often referred to as CHIEF by the phone supplier).
The additional contacts on the switches are for line/extension switching and this model looks like it may even contain a ringing generator.

I have a copy of a catalogue somewhere which may include your phone, feel free to PM me if you would like a copy to look at

Edit - I have just re read some of the comments and suspect that it may well be the equivalent of Plan 12A that Ian has posted a link to, the additional bell being contained in the phone rather than externally as shown on the N diagram.

Regards

Andrew
But the phone in the photo has SEC'T not SEC'Y. Private companies used different terminology to the GPO/PO/BT.
Plus you may not have noticed it is a New Zealand telephone in New Zealand. As I mentioned the 700 style phones that I have from New Zealand working on my NZPO PABX were made by GEC in New Zealand. Hence the different DC bell - non-BPO pattern.
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Old 16th Jun 2019, 12:49 am   #15
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Default Re: 746 phone with extra buttons

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Originally Posted by Dave Moll View Post
Presumably, unless the extras are a later modication, the actual model number may be something other than 746. Please can you confirm what is stamped on the base.
It has 746 on the base (Model 100 GEC). These phones were made in New Zealand (where I am).


Quote:
Originally Posted by Pellseinydd View Post
See N1248 for a picture of the Plan 12A telephone with a 'SEC'T' button for secrecy.
That's exactly what it is - it's mentioned in the text on that page that it's a secrecy function to switch out the extension for privacy.
Thanks for the info and thank you to everyone else who has offered thoughts and comments.
Certainly opened some interesting debate on this!
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Old 16th Jun 2019, 10:49 am   #16
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Default Re: 746 phone with extra buttons

I've got an early 1980s training video which has some footage of someone dialling a number for a computer with a modem using a 700 series phone, & then pressing a switch like this one on the top to connect the modem to the line.
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Old 16th Jun 2019, 11:39 am   #17
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Default Re: 746 phone with extra buttons

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I've got an early 1980s training video which has some footage of someone dialling a number for a computer with a modem using a 700 series phone, & then pressing a switch like this one on the top to connect the modem to the line.
The GPO/PO/BT had a large range of buttons for use on 7XX series phones by - see diagram N849
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Old 16th Jun 2019, 11:47 am   #18
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Default Re: 746 phone with extra buttons

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Could the SEC'T be used as a cut off for the transmitter- the same as mute used today?
GPO/PO/BT telephones used a different handset (Handset No 6) fitted with a switch to cut off the transmitter by shorting it out on most telephones or disconnecting the transmitter circuit on supervisors handsets or local battery telephones. See N861 for connections
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Old 16th Jun 2019, 1:55 pm   #19
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Default Re: 746 phone with extra buttons

As I understand it, a 'Telephone 746' is defined by the case used (!). The 746 case allows for one (wide) or 2 (narrower) buttons to be fitted in the middle above the dial. The older 706 only allowed for one button. One button might be used as a bell on/off switch or a recall button. Two buttons were needed for Plan 105 internal extensions (the extension telephones to a Planset), so a 706 could not have been used there (you'd need a 710), whereas the 746 could. I suspect that was the main reason for allowing 2 buttons on the 746.

There were 4-button telephones with much the same electronics, the Telephone 710 and the Telephone 740. On those the buttons were quite widely spaced, not like the 2 adjacent buttons on a 746.

I've seen (and indeed own)telephones used with PO modems (indeed there was even a modem (Modem 13A or Modem 13B) in a plinth under a Telephone 740). But always the 4-button version of the telephone. I've never seen it down with the 2 adjacent buttons on a 746.

Also remember there were non-GPO versions of these telephones. The Plessey 'Secretarial' sets, basically their version of the Planset, was a Telephone 710 case + electroncis with switches, a buzzer, etc crammed inside. The buttons on those were simply coloured (red, white, green, blue in some order), not labelled.
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Old 16th Jun 2019, 2:15 pm   #20
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Default Re: 746 phone with extra buttons

Quote:
Originally Posted by Pellseinydd View Post
Quote:
Originally Posted by Euros1951 View Post
Could the SEC'T be used as a cut off for the transmitter- the same as mute used today?
GPO/PO/BT telephones used a different handset (Handset No 6) fitted with a switch to cut off the transmitter by shorting it out on most telephones or disconnecting the transmitter circuit on supervisors handsets or local battery telephones. See N861 for connections
GPO/PO/BT telephones used a different handset (Handset No 6). I agree,and am aware, Pellseinydd, but it was only a suggestion,as I am unsure what was done in New Zealand.
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