Re: SIA, Contact ID, 4/2, 3/1

[Bob La Londe <alarm_wizard@xxxxxxxxxxx>]

On Oct 15, 12:10 pm, "JohnO" <johno@@&%heathkit##.com> wrote:
> Hey guys, it's been about three years since I was here pestering you for
> basic info about alarm systems, and our training course needs an update, so
> I'm back again. (Good to see you all still picking on each other.... ;-) )
>
> The course I'm working on is based on CompTIA's new DHTI+ certification. One
> of the certification domains covers security and surveillance systems, and
> one of the sub-domains reads:
>
> Monitoring Formats
>         -SIA and Contact ID
>         -4/2 and 3/2
>
> I've done a basic google search of this group, and the web, and I haven't
> found quite what I need. Or let's put it this way...I have an idea what
> these terms mean, but can't find info that helps me understand them well
> enough to explain it to someone else. Does someone know of a site or article
> somewhere that describes these monitor data formats in basic terms? Your
> discussions here in the NG tend towards the pro/con at a professional tech
> discussion level, naturally, and I can't follow along with some of that.
>
> Thanks!
>
> -John O
> Heathkit Ed Systems

I'll let Mark Leuck answer about SIA, but I can tell you about 4X2 3X2
and CID.

There is an old telephone calling method where you turn a little dial
and as the dial rotates back into place it momentarily breaks the
contact between the telephone and the telephone line.  If it does it
nine times in a row without a pause then the phone has dialed the
number nine.  ten a zero, three a three etc etc...  Alarm panels took
advanatge of this format to send numbers to an alarm central station.
Its as reliable as your phone line's ability to rotary dial.  I have
been told there are some telephone exchanges out there that no longer
support rotary dialing, but I have not personally worked on any except
private branch exchanges where that is the case.

In pulse format the panel is set to send a 3 or 4 digit string of
pulses for the account number and then a 1 or 2 digit string of pulses
for the alarm signal.  The receiver sends a recongnition signal and
its done.

CID works basically the same way except it sends individual tones just
like a touch tone telephone.  CID has an extended charachter set as it
supports 16 digits instead of the ten digits of a rotary format.  This
gives the ability to assign more account numbers and more zones and
more information strings.  Because CID just sends a momentary tone
insead of a string of pulses seperated by a pause for each digit in
can send the information much faster.  This has two benefits.  It can
be more cost effective from a time connected standpoint.  It can also
allow for more information to be sent.  In most CID format reporting
it sends the account number, a report type, and an identifier such as
a zone number or user number and sometimes partituion information.
Some panels like the P800/1 by Napco send an abbreviated CID format,
and some like the FBII XL4 allow you to redefine the CID types.

One possible disadvantage to CID is that it can get distorted beyond
the ability to recognize the individual tones by over utilized long
distance carriers.  Basically their service sounds like two tin cans
on a string.  It is echoey and distorted.  This is often caused by
over compressing the voice data to force it over limited bandwidth.
The human ear can discern variations in sound and often voice users
don't complain because they can get the message, but the hardware is
looking for clean clear tones.

Also, some manufacturers and some older models of panels don't
implement CID well.  I have experienced that the FBII XL3 and XL31
seem to have problems in CID mode and send the signals over and over
again.  I have also experience random lockups during testing with some
FireLite panels sending CID.

In general I prefer to send CID because:

1. It costs me less money.
2. Sends more precise information
3. Because the types of signals received are predefined it reduces the
likelihood of programming screwups by technicians.

However:
Whenever I have a problem with funky communications problems I switch
to pulse format and see if the problem goes away.

I hope this is a good basic laymans description of how it works so
that you can wrap your mind around it.