Communications
SEM Security Systems
a division of Southeast Mobility Inc
In order for your alarm system to notify the police that someone has broken into
your home it must be able to communicate. In years passed that has been done
over the premise telephone lines. Today there are other technologies available
and as a matter of fact, phones lines are going to soon become of thing of the
past for alarm communications. A lot of customers are doing away with their
home phone lines and relying strictly on their cell phones. We'll look at those
other technologies in a minute but first let me clarify something about how your
alarm system communicates your alarm over your phone line.
The panel is connected to the phone line, the wire is run from the box on the
outside of your building to the panel and then another set of wires goes back to
the box and is connected to the wires that are coming into your home or
business. When an alarm occurs, the panel picks up the phone line and makes
a call just as you do when you make a call. I've had people argue with me that
the monitoring center will know it immediately if someone cuts the phone line on
their alarm system. In a word, NOT. If your system is on a bank, large jewelry
store or other high risk application, you alarm system may be attached to a full
time dedicated data line that is in constant communications with the monitoring
computer. If that line gets cut then the computer knows that it has lost
communications with the panel and it will create an alarm that the operator will
dispatch the police on. 99.9% of the alarm panels that are in operation today
are attached to a standard plain ole telephone service line (POTS line) which
picks up the line, dials a ten digit number, and then communicates to the
monitoring computer, if the phone line gets cut, it haint calling no one folks.
Now that I have that off my chest, let's go back and talk about how that phone
line is hooked to the panel. The wire runs from the box outside, to the panel
then back to the box outside where it is hooked up to the wires that are coming
inside the home or business, why is it wired that way? Have you ever been on
the phone and had someone in the other room pick up a phone and start
dialing? What happened? You heard the dialing in your ear but their call didn't
go through, so what would happen if you were talking on your phone at home
late one night and someone kicked in the back door? By running the wiring from
the box outside through the panel then to the rest of the home, it enables the
panel to take control of the line when needed. If you are on that line, your call
will be cut off, the panel will complete it's call and then turn the line back over to
you. If your alarm goes off and you hear dialing over the phone line, then it is
not wired correctly and you should report it to your alarm company.
So why are POTS lines going to become a thing of the past? In a word,
technology. That same wire that use to bring only a dial tone into your home can
now be used to deliver telephone, television, and internet communications. This
is done by using digital communications. Even if you still have a POTS line, your
analog call may be converted to digital further down the line. Once your call
arrives at the switching office it may be converted to digital and sent down the
line with a hundred other calls simultaneously. At the next switching office, calls
that don't need to go any further are picked off, converted back to analog and
delivered to your other party on their POTS line. The problem as it relates to
your alarm panel is in the conversion process. Your panel communicates with
the monitoring computer by sending it a series of tones. When those tones are
converted from analog to digital and then back to analog, the tones are often
not accurately reproduced which makes it impossible for the monitoring
computer to understand the message. Sometimes the message is completely
garbled and sometimes it is misinterpreted and the monitoring computer will
indicate an alarm at the wrong residence or maybe the correct residence but
indicate the wrong zone.
To make matters worse, the Federal Communications Commission (FCC) has
given the go ahead to the phone companies to set sunset dates on POTS lines
beginning 2014. What this means is that the phone company has the right to
notify you that your POTS line will no longer be serviced and you will have to
convert to digital communications or no longer have telephone service.
So, what do we do about all of this. We can't stop progress so we have to get
on the band wagon and start allowing our alarms to communicate digitally. We
have a couple of alternatives, an IP communicator or a cellular communicator.
The IP communicator is simply an interface device that is added to your alarm
system that allows your panel to communicate over your internet directly to the
monitoring computer, and it is quick. The typical alarm report over a POTS line
takes about 12 to 18 seconds. That is from the time the alarm sounds until the
operator has the information on the screen to process. With an IP
communicator that time is reduced to 2 seconds. Our customers who have IP
communicators regularly report that their phone is ringing before they can get
their code punched in to turn the alarm off. What are the draw backs? Well, you
are still communicating, in most cases, over a phone line or cable wire which is
accessible outside the home and therefore is subject to be cut by the would be
burglar. If your internet goes down, your panel can't communicate. This means
that you will need to add a battery backup to your cable or dsl modem so that it
will continue to function even if the ac power goes off.
The cellular communicator is another interface device that can be added to your
alarm system that allows it to communicate to the monitoring computer via the
cell phone network. It is self contained, battery backed up, and generally faster
than a POTS line but not as quick as an IP communicator. Of course you will
need cell phone coverage at your premise. Also, the unit is located inside the
protected area making it difficult for a would be burglar reach it to disable it.
A few years from now these alternative forms of communications will become
the rule rather than the "alternative", but for now the POTS line is the standard
and therefore the alternatives come at an additional charge.