H/W Development question

["Robert Welsh" <bob-ukha@xxxxxxx>]

One for the hardware techies out there...

I discovered last night that my alarm system has a number of output
terminals which can be use to drive external devices e.g. ARC or
diallers.

One of the terminals is a "set" indicator - which is exactly what
I'm
looking for.

This terminal is 12V normally and drops to 0V on "set"
condition.
There's also a 13V and a 0V terminal offered on the PCB.

What I'm not sure is how to start designing something simple that I
could connect to a serial port to monitor this.
It seems to me that it's probably the kind of thing that must have been
developed 100 times by 100 different people.

Any pointers would be appreciated.

Robert
(fundamentally a software guy, with a rusty hardware background)

PS - Most developments I see around use RS232 ports....is USB
development that much harder ?




http://www.automatedhome.co.uk
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