On Thu, 26 Oct 2000, Tony Duell wrote:
> We had (I doubt any are still in use) some modems over here that (IIRC)
> were made by Plessey, and rented by the GPO (who ran the telephone
> service, and who owned everything connected to it at the time. You had to
> rent whatever equipment you wanted from them). Anyway, the modems in
> question were large -- about 2/3 the size of a PC/AT system box -- metal
> cases with (mormally) 4 plug-in modules inside. They were the PSU,
> Modulator, Demodulator, and control. It was all discrete components
> (well, the 'control' module, which did things like ring detection,
> hookswitch, etc used a number of relays). The modulator was either a pair
> of oscillators and a way to swich between them, or a single VCO with a
> circuit to switch the control voltage.
I just picked up something like this a few weeks ago. I believe it was
all discrete components on about 4 plug-in modules as you describe, but
I've forgotten who manufactured it. I'll take a peek at it when I get
home.
Sellam Ismail Vintage Computer Festival
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Received on Thu Oct 26 2000 - 17:21:46 BST