Telephony switches - is there anyone out there collecting these?

[Rob]

On Sun, 1 Jul 2007 00:12:50 +2500 (BST), Tony Duell
<ard at p850ug1.demon.co.uk> wrote:

>
> Incidentally, the 2B has a ring-detect relay inside, which asserts Ring
> Indicate (pin 22) of the RS232 connector when trigger. You have to make a
> few more conenctions to tbe barrier strip, in particular one to the bell
> wire in the telephone cabe, and add a 3K resistor (or a Thermistor 13A?).

Yes, I think i did that.. the beeb looped waiting for ring detect, and
lifted dtr to answer the line. I then had a background routine that
polled carrier detect and interrupted the bbs software on line drop.

>
> I built a box off TTL that sits on top of the 2B and which does
> auto-answer (inculuding hanging up after a suitable time delay if it
> looses carrier), dialing (by toggling the DTR line the right number of
> times, etc. I probablty still have the scheamtics somewhere, along with
> the notes I made on linking up the ring detect relay.

Ingenious,, probably a bit beyond me at the time though..


> > I remember being fascinated by the kit they had available, but it was
>
> A lot of it seemed to be very expensive and not in particularly good
> condition.

indeed ... I didn't buy anything else from there.. I think they had
reuters board beeb's though, which almost tempted me..

>
> > tricky enough getting the 2B home to Manchester..  I seem to recall I
>
> It couldn't be worse than the time I took a GT40 (complete with monitor)
> on a train from Bristol to London :-)

I beat it several years later by carrying a BBC B, dual floppy drives,
box of software, and a very heavy amcom 10MB hard drive unit in it's
shipping box on the train back down to London..  I'm fairly sure I
never tried carrying a monitor tht far though!!

Rob