[tech] Door Circuitry

[James Andrewartha]

On Sun, 29 Aug 2010, David Adam wrote:

> 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.

strings /usr/sbin/opendoor suggests 'ATH1F' and 'ATH0F'.

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