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TonyDuell · 16th Jun 2019, 1:55 pm

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.

16th Jun 2019, 1:55 pm	#19
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,225	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.