Author Topic: GPO 1/764 pushbutton - A surprising oops moment!!  (Read 849 times)

Offline twocvbloke

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Re: GPO 1/764 pushbutton - A surprising oops moment!!
« Reply #30 on: June 02, 2019, 09:51:22 AM »
The GPO was still quite archaic (they stuck with mechanical exchanges for far longer than the US) when the Bell System was already releasing Touch Tone dialling telephones, as far as I'm aware, TT, let alone push-button, didn't become a common thing here in the UK until at least the 1980s after the GPO was split into The Post Office and British Telecom, and the latter had to basically start becoming more technologically advanced than it was under the GPO's rule... :)

And as for electronics, the typical "that'll do" thing tended to be the staple here, transistors did the job & were cheaper to obtain, so "that'll do", given that an appropriate IC could have been used to generate dial pulses and have been a far more compact solution, but they didn't use that sadly...

But still, it makes our telephones somewhat unique in the way they stuck with what they knew for so long, but that they also designed them to be long-lasting and therefore still working today, give or take a few repairs or additional parts... :)

Offline twocvbloke

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Re: GPO 1/764 pushbutton - A surprising oops moment!!
« Reply #31 on: June 04, 2019, 08:34:47 AM »
Finally dug out my PAP2T to test the phone, and it's not ringing!!! Either I've fluffed up the wiring, or there's something wrong, presently just going through the N-diagram now to make sure I haven't missed anything or wired it up incorrectly...  ???

Also being driven nuts by someone running a two-stroke engined something outside really loudly......

EDIT:
Never mind, it was a PEBCAK with my wiring in the Block Terminal...  ::)
« Last Edit: June 04, 2019, 08:56:37 AM by twocvbloke »

Offline twocvbloke

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Re: GPO 1/764 pushbutton - A surprising oops moment!!
« Reply #32 on: June 04, 2019, 09:46:32 AM »
I decided to brave using a protected LiPo battery (4.2v fully charged, compared to the 4.8v of a NiCad or NiMH, hence the need for protection), and hooking it up to the battery connector, the dial has come to life!!!  ;D

The battery is being charged at a low current of 2.8mA, so shouldn't cause the LiPo to go pop, so not too much of an issue there, though I think the LiPo needs slightly more to be properly charged, but I'm no expert and frankly I don't want any flames in this phone thankyouverymuch...  :o

Anyway, dialling a string of numbers, the mercury relay does some very quiet clicks at a reasonably proper 10pps rate, so quiet I doubt the stupid noise-gate nonsense on my mobile phone's camera would allow it to be picked up, so need to think about how to record that, but I'm rather happy to hear it ticking away as I push buttons...  ;D