[tech] Door Circuitry

David Adam zanchey at ucc.gu.uwa.edu.au
Sun Aug 29 23:49:10 WST 2010


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 
:-)


zanchey at ucc.gu.uwa.edu.au



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