Phone line backup
Noel Madrigal
I just visited the Napco site and they advertised a phone line monitor
circuit. Are they relying on some sort of backup to contact the
monitoring station or are they hoping that triggering the siren(s)
will be enough to scare the crooks?
Do phone line backups exist? Can someone point me to further
information on these?
Thanks in advance.
Robert L Bass
(Noel Madrigal) wrote:
There are several options for phone lines -- protection, detection and
backup:
PROTECTION -- Consists of hiding or guarding the phone lines. Commonly
used methods include bruying the line and bringing it into the house
below grade; covering the outside drop on the wall with 3/4" or larger
galvanized threaded pipe; bringing the line (aerial drop) into the
house at a hight that is inaccessible; etc.
All of these methods involve making the line difficult to cut. None of
them makes it impossible to cut. Also, a savvy thief (not too common
but they do exist) may cut the line at the pole. You generally can't
do anything to protect the line at the pole. The telco get's quite
finicky about customers working on their outside plant system for some
reason. :-)
DETECTION -- This often consists of an add-on or built-in circuit to
detect the presence of proper voltage and/or current in the line(s)
connected to the alarm panel.
In the US most phone lines run about 48-51 VDC while the phone is
on-hook (no one is using it). The voltage drops to around 6 VDC when
you lift the handset. There's also an interruped, 90VAC (or
thereabouts) pulse when the phone is ringing.
The line cut detection circuitry simply looks for the presence of
proper voltage, etc. If none is detected a timer starts. After a
programmed interval the system will either generate a keypad alert, go
into full alarm condition or report via some other means, depending on
the way your system has been programmed.
In the case of Napco systems, the line cut detection is selected as an
option and the time delay before tripping is set during programming.
The system can respond in any of the manner described above -- again,
depending on which options you check when you program the system. It's
easy to select, deselect and adjust these things using Napco's
PCD-3000 software, which is a free download. E-mail me if you need
assistance or if you want a copy of the program.
BACKUP -- This involves having one or more alternate means of
reporting the alarm to your central station, pager, etc. The panel may
accomodate two regular phone lines (Napco MA-3000 system with
Dual-Line Dialer option installed, for example). This is fine for a
fire alarm where the most frequent problem is accidental line failure.
A burglar alarm system would not gain much from dual telco lines as
both could be cut as easily as one.
Another means of backup is long range radio. There are several popular
schema involving radio telemtry. Options include one-way transmitters
or two-way (polling) transcievers. There are many companies that can
provide this option. It is sometimes expensive, but usually quite
reliable. I'm familiar with the basics but it's not my area of
expertise. Perhaps another poster will add more on the subject.
One type of land line backup that is gaining in popularity is
cellular. There are several companies that make "fixed station" cell
phones. These are often designed to read the DTMF (touch tone) digits
the alarm system tries to dial and translate them into cell phone
digital dialing codes, then transmit the call to the central station
receiver. The alarm panel usually doesn't even "know" it is dialing
through the cellular network. Communication is completed in the normal
manner.
Because cellular calls cost the system is usually set up to first try
to dial out over the normal telco lines. If the call doesn't go
through or if the cell phone unit has sensed a line loss and
activated, the call then goes through the cellular network.
There are a number of other means of backup which are available in
some areas through various providers. I have only touched the surface
in this short note. Hope it helps.
Blue Skies,
Robert L Bass
========================>
Bass Home Electronics
80 Bentwood Road
W Hartford, CT 06107
alar...@BassHome.com
http://www.BassHome.com
860-561-9542 Voice
860-521-2143 Fax
========================>
Robert Dolph
I always like leaving the real phone line hidden and preferably buried,
while having a dummy line exposed. Then if they cut the phone line you are
okay. Also wireless repeaters to the neighbors phones works good.
Bob Dolph
Ron Wies
Hiding the phone line is a reasonable first step. We operate a two way long
range wireless system. It is very reliable and offers a high degree of security
but is very expensive. We spent about $40K setting the system up and today have
less than 5o end users monitored on it. Needless to say, this was a marketing
error.
Cellemetry looks like the most promicing option on the horizon. A firm called
Uplink in Atlanta GA. operated the system. Unfortunatly it is not yet available
everywhere. Radionics and Caddx both offer control panels that will plug
directly into an Uplink unit. The Uplink radio unit sells for around $100.00
and transmits alarms on the data channel of the cellulsr network.
Look at http://www.com/bscc/pr022597.html for some information concerning the
product line.
Later,
Ron--
Barry May
I would like to add to the radio backup that Robert referred to. I am a
sales rep for a Long Range Radio company. If you have any questions, please
drop a note in this thread.
Barry May
Security Consultant
AES IntelliNet Rep.
ba...@security-zone.com
Robert L Bass
You must have a lot of knowledge on this aspect of security. How about
posting a brief overview of the systems you work with, the most
important features and drawbacks of various types, etc.
Thanks
On Mon, 20 Apr 1998 03:30:03 GMT, Barry May <ba...@security-zone.com>
wrote:
Ed Heyden
Noel Madrigal wrote:
>
> I just visited the Napco site and they advertised a phone line monitor
> circuit. Are they relying on some sort of backup to contact the
> monitoring station or are they hoping that triggering the siren(s)
> will be enough to scare the crooks?
>
> Do phone line backups exist? Can someone point me to further
> information on these?
>
Look into UPLINK Cell Service. They have a back up cell unit that boards
into your panel and will offer a true back up to CS or pager.
Ed Heyden
Sensorytech Security
Morgantown,WV
Barry May
AES IntelliNet is one of a handful of companies offering Long Range Radio alarm
monitoring systems.
Most systems on the market are one way devices that report to a tower site close
to the protected location. Supervision consists of a daily test timer. In order
to insure that the signal will get through, it has to be transmitted numerous
times. Some systems will resend the signal in excess of 50 times. If there is
excessive alarm traffic or other radio interferrence, the signal may not get
through at all. There is no supervision on the signal transmitted. In other
words, your alarm system doesn't know if the signal was ever received by the
central station.
Two way radio systems do have the alarm signal transmission supervision in
addition to the 24 hour test timer. Each alarm transmission is sent once and
expects an acknowledgement from the central station. If no acknowledgement is
received than another alarm signal is transmitted. This also reduces the on air
traffic (sent only once rather than 50 times) allowing cleaner operation and
higher capacity on the system.
AES IntelliNet differs from most others in that each subscriber unit also doubles
as a repeater for any other subscriber in the network. Subscribers make up the
network rather than towers. Each alarm site is linked to the network by a smart
subscriber unit (both transceiver and repeater). Alarm signals are sent through
the network to the central station. A signal is transmitted directly to the
central receiver if it is within radio range, or is relayed through one or more
smart transceivers. Signals always follow the shortest, most reliable route
available.
Redundancy is a key feature of the network. From any given subscriber unit,
there are many different routes the alarm message can take. If an alarm signal
cannot be sent by one route, the intelligent transceiver automatically selects
the next best route. Systems using towers are critical path systems. If the
tower radio fails, the alarms is out of communications. AES answers this with
the multi-path redundancy that the smart transceiver/repeater provides.
With each subscriber also providing repeater capability, towers are not necessary
(although they are sometimes used). The repeatability provides coverage into
areas that can be shaded by a tower only system. Coverage is comprehensive,
redundant and fully supervised. There is no other Long Range Radio Alarm
Monitoring system like it in the world.
Each subscriber has 8 discrete zones (close, open or voltage circuits) This can
be expanded to 72 zones. Up to 64 relays can be operated at each subscriber unit
with add on boards is units of 8. The system can interface with DMP, Napco and
other panels to send all data. The AES IntelliTap is a passive phone line
monitor that reads alarm data of the phone line output of the digital
communicator and transmitts it by radio. This can handle 4X2 and Ademco Contact
ID.
The subscriber unit can last 4-6 days on a 7 ah battery. Each transmission is
only two tenths of a second.
I guess I went on about this discription. If you have specific questions about
the AES system, I'll be happy to provide the answer.
hol...@heselectronics.com
In article <353E87...@westco.net>,
Ed Heyden <big...@westco.net> wrote:
>
> Noel Madrigal wrote:
> >
> > I just visited the Napco site and they advertised a phone line monitor
> > circuit. Are they relying on some sort of backup to contact the
> > monitoring station or are they hoping that triggering the siren(s)
> > will be enough to scare the crooks?
> >
> > Do phone line backups exist? Can someone point me to further
> > information on these?
> >
>
> Look into UPLINK Cell Service. They have a back up cell unit that boards
> into your panel and will offer a true back up to CS or pager.
>
> Ed Heyden
> Sensorytech Security
> Morgantown,WV
A company called, "Senaphone" makes some very unique phone dialers. I
haven't got prices yet, but hope to distribute their products as well in
the near future.
When available, it'll be posted to my website http://www.heselectronics.com
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