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Old 18th May 2019, 1:34 am   #1
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 1,338
Default GPO/BT Call Progress Tones?


I didn't get my own mobile until only a few years ago so relied on call–boxes much later than most people I knew when I was younger, and I remember the residential phone books always had the phone call progress tones described in the "General Information" pages as follows:–

A) Dial Tone (continuous purring or higher–pitch continuous tone) – Dial number desired, not forgetting area code;

B) Ringing Tone (a repeated burr–burr) – The equipment is trying to call the dialled number;

C) Engaged Tone (A repeated single note) – the called number is busy – please try again a few minutes later;

Now on one or two occasions I heard two variations of this – one was a repeated "up" and a "down" tone and the second was a very short "pip" followed by a much longer "beep", again continuouly repeated, at roughly the same pitch – I never saw these mentioned in the phone books! Can any 'phone experts enlighten me?

D) Number Unobtainable Tone (a continuous note) – the called number or line is not in service;

E) Pay Tone (a series of rapid pips) – instructs call–box users to insert money to begin or continue the call.

Those were the official descriptions that were printed, if my memory serves me correctly.

What happened if you picked the phone up and carried on listening whilst any of these tones (apart from ringing–tone of course!) were in progress – did they carry on indefinitely?

Does anyone recall ever hearing any unusual tones/sounds on the lines apart from those described above, and what about announcements? – I remember that phone books said "occasionally recorded announcements may be used instead of tones in some areas", but I don't think I ever once heard any!

Chris Williams
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

Last edited by Chris55000; 18th May 2019 at 1:41 am.
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