[tech] Door Circuitry

[David Adam]

On Sun, 29 Aug 2010, David Adam wrote:

> On Sun, 29 Aug 2010, Bob Adamson wrote:
> > Sad news - our door relay has kicked the bucket. Somehow the electronic lock
> > got a short in it, killing the modem (!) that drives the relay. Of course,
> > being UCC, this modem was a complete box of hackery. Adrian and myself are
> > working on a simple circuit to replace it, but haven't had any luck yet.
> > 
> > If anyone knows anything about how the old setup worked (particularly the
> > success/failure sensing in the binary) please give me a yell.
> 
> >From http://www.ucc.gu.uwa.edu.au/services/door.ucc
>   The door lock is switched using the On-Hook relay of a modem. This 
>   provides a cheap, reliable serial interface to the door lock. 
> 
> You need to send ATD (or possibly ATH) down the serial line to make the 
> modem pick up the phone line. The thought occurs that you probably didn't 
> know that this afternoon which may have been why you couldn't get it to work 
> :-)

Actually it's A0. I think.

[DAA]