[ExI] Telephone hacking

Aware aware at awareresearch.com
Thu Jan 7 22:04:57 UTC 2010


On Thu, Jan 7, 2010 at 1:22 PM, spike <spike66 at att.net> wrote:

> Recall those things had a capacitor in them,
> which had to charge, and the discharge cycle would cause the ring to be the
> usual intermittent signal.  The only reason I know about this is that back
> in the old days when long distance phone calls cost a lot of money, people
> would regularly signal each other by prearranging to call at a certain time;
> the number of rings would be translated to a message.  An example is the
> signal agreed upon in my own misspent youth regarding the approaching
> redcoats: one if by land, two if by sea.

Reminds me of one of the things I did in MY misspent youth:  It turns
out that while the phone was ringing, even though it hadn't been
answered (picked up) there was already an audio connection available
through the circuit.  I had a friend about 30 miles away (long
distance charges) but we were able to communicate by voice--better
than counting number of rings--while the phone was ringing, by using
audio amplifiers (essentially an intercom) with capacitive coupling to
block the 45VDC and diode clipping to limit the 90VAC ring signal.

Oh yeah, I was a wild electronics experimenter in my youth...

- Jef



More information about the extropy-chat mailing list