Re: Napco MA3000 - Dialer Test on both Lines?

[Nomen Nescio <nobody@xxxxxxxxx>]

Bass said:

>Ok.  Two programmable relays are set to interrupt a  24-hour test zone and
>to short phone line 1 at the designated time.  This causes the panel to
>report the 24-hour zone as a silent alarm, but the code/zone is configured
>at the c-station to be viewed as a test signal.  A third relay can be
>triggered by "general trouble" and run in series with the phone shorting
>relay so that line 1 will not short out if the panel is currently
>experiencing a trouble condition.

That doesn't work so well either.

When the relay shorts phone line 1, the panel doesn't know that line 1 is
inoperative, therefore it will dial unsuccessfully on line 1 until the
panel's programming forces it to switch to line 2.  But suppose line 2 is
bad?  The panel will attempt to dial out on both lines, I'm guessing eight
attempts per line.  When the relay times out and line 1 restores, your test
signal will arrive on schedule -- via line 1.  The failure on line 2 is not
detected.

Now, you could fix this by programming the relay activation time to be
longer than the maximum number of dialing attempts.  However, since you are
shorting the phone line, that would trip the line fault monitor, resulting
in more dialing attempts, and eventually, a phone line trouble and restore.

More importantly, if line 2 really is inoperative and you short out line 1,
the fire alarm system will be unable to report an alarm for however long it
takes to run through the maximum dialing attempts on both phone lines.
Fifteen minutes or so?

I could be mistaken about this, but connecting your auxiliary relay to
short out the phone line probably violates FCC Part 68, since that relay is
not approved terminal equipment.  I suspect, but have not checked, that
equipment that places a dead short across tip and ring is also forbidden.

Anything I've overlooked or misunderstood?

-  badenov