Re: H/W Development question

["the_home_automator <db@xxxxxxx>" <db@xxxxxxx>]

I dont know the provenence of your alarm system, but alarms in 
general should be isolated and self contained, hence connecting the 
internal outputs to kit that is outside the box is frowned upon, and 
would probably bust your BS4737 compliance.

The easiest interface with signalling outputs is to use a high 
sensitivity relay, eg RS 349-254.  This will then provide a "volt
free" interface (ie just the relay contacts) which you can connect to
anything required to monitor your alarm.

Serial port: VIOM, a module from controlanything.com or an ADAM or 
ICS, or just a control pin on the serial or parallel port.

--- In ukha_d@xxxxxxx, "Robert Welsh" <bob-ukha@s...>
wrote:
> 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 ?



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