Alarm Communications Over IP & Cellular Networks

Alarm Monitoring in the Cellular and Internet Ageit possible for some solutions providers to allow
The onslaught of mobile phones, Voice over IPthe use of regular low cost 'off the shelf' VoIP
and Instant Messaging has changed the way weATA's for the reliable transmission of alarm signals
communicate. GSM and fixed & wirelessover the Internet. This obviously provides huge
Internet is becoming more widespread and lesscost benefits to both installers and end users as
expensive each year and this will have an effectdevices can be sourced locally and existing
on the way security systems might communicateInternet connections can be utilized as the
in the future. Consumers are ever keener to taketransmission path.
advantage of new technologies and it is importantIt should be noted that these solutions do not use
that the security industry adapts quickly and doesor rely on the services of a VoIP service
not get left behind.provider. Afully controlled connection direct from
Demise of the Public Switched Telephonethe VoIP ATA device to the monitoring server
Networkeffectively creates a private network.
For decades, PSTN has been the chosenCONS: All fixed wire IP solutions are subject to
communication platform for the transmission ofsabotage from line cut which prevent devices
alarm signals. Today, many are predicting its daysconnecting to the network.
are numbered. Two transmission paths haveDual Path Signaling
emerged as the preferred methods ofEven trusty old PSTN was not immune from
communication between an alarm panel andnetwork failure and was definitely prone to line
Monitoring Centre - IP (the Internet) and GSM.cut attacks. The line cut vulnerability has been
This article will examine the pros and cons ofremoved with the supervised connections
each.incorporated by IP and GPRS solutions but it is
GSM Wireless Networksclear that even they cannot guarantee 100%
In today's high tech world, almost everybodynetwork uptime.
owns a mobile phone. The perception is that GSMWith this in mind, many consumers refuse to rely
networks are very reliable and rarely suffer from100% on a single transmission path and insist on a
network outages. This makes GSM a viablesecondary backup path. There are several
platform for alarm communications and threecombinations that can be used to provide a dual
different technologies can be employed for signalpath solution with different levels of security. The
transmission - SMS, Voice and Data.lowest level dual path solution is provided by using
The reliability of SMS varies greatly from countrya combination of PSTN and GSM. As PSTN
to country and delays in message delivery rule itcontinues to decline and neither path allows for
out from being considered a serious option incost efficient network supervision, this is not a
countries where messages can often be delayedfuture-proof option.
for many hours. In countries that do notA more popular combination for cost sensitive
experience such delays, SMS can be a good lowapplications is the use of the Internet as the
cost method of alarm communication, however, itprimary path and GSM Voice as the secondary
is often not popular with alarm monitoringpath. The Internet path benefits from network
companies as it opens up the possibility of selfsupervision and the GSM path can take over if
monitoring where messages can be sent directlythe primary path fails. Certain model VoIP ATA's
to the end users mobile phone.used in conjunction with GSM dialer have the
The use of a GSM Dialer/Communicator allows anability to send signals over the Internet when a
alarm panel modem to dial out and make a phonepanel dials the primary telephone number and
call to the Monitoring Centre over the GSMover the GSM network when it dials the
network. When a conventional analogue alarmsecondary telephone number.
receiver answers the call, an audio/voice channelA similar level of security can be provided by
is opened up and the alarm panel canusing GPRS as the primary path and PSTN as the
communicate with the receiver just as it wouldsecondary path. Some solutions providers claim a
over a PSTN line. This technology benefits fromdual path capability by using GPRS as the primary
being alarm protocol independent and industrypath and GSM Voice or SMS as a secondary path.
experts claim a transmission success rate ofOthers claim dual path capability by using two
somewhere between 80% and 100%.GPRS SIM cards. These claims are somewhat
PROS: Both SMS and Voice benefit from lowmisguided as a GSM jammer will effectively
equipment costs and low network rates.prevent all communications over the GSM
CONS: SMS and Voice technologies do not allownetwork regardless of which method is used. GSM
for the cost efficient supervision of a connectioncan only ever be treated as a single path even
to the Monitoring Centre and often the firstthough it allows for 3 different methods (SMS,
anyone gets to know about sabotage or networkVoice & GPRS) of transmission.
failure is when a scheduled signal, or worse, anHigh security applications demand two
emergency signal fails to arrive.independently supervised transmission paths and
GPRS Wireless Networksthis is usually achieved by using the Internet as
The use of a GPRS data plan overcomes thisthe primary path and GPRS as the secondary
problem and allows constant supervision of thepath. Both are fully supervised, so even if the
connectionbetween the protected premises andprimary Internet path fails the system is left with
the Monitoring Centre. A GPRS device uses thea supervised alternative path.
GSM network to achieve an 'always on' wirelessSome solutions providers claim that by using a
connection to the Internet. Once connected, it cancombination of broadband Internet, GPRS, GSM,
communicate using Internet Protocols (IP) just likePSTN and
any other Internet enabled device. This allows theDialup Internet their product supports 5 paths. As
sending of regular heartbeats to the monitoringboth broadband and Dialup Internet generally
server so that any equipment failure, sabotage ordepend on the availability of a PSTN line and
loss of network can be detected within seconds.GPRS depends on a GSM connection a more
GPRS devices do not support audio/voiceaccurate claim would be that such a solution can
communications, so any alarm signals usinguse 5 different methods of communication over
standard protocols such as Ademco Contact IDtwo independent transmission paths. A dual path
or Fast Format have to be converted fromsolution with bells and whistles.
analogue to digital within the device itself. This isRemote Programming and Audio Verification
referred to as Dialer Capture. GPRS enabledIf it is important for your company to retain the
devices are more expensive than SMS and Voiceability to remotely program control panels or to
devices and the cost of data plans vary widelyopen up a two way audio connection to the
from country to country. Asian countries tend tomonitored site then you should carefully consider
have very reasonable rates whereas rates inwhich of the above mentioned solutions you
North America are very restrictive.chose. It is not possible to open up an audio path
CONS: All of the GSM technologies are vulnerableusing GPRS. It is possible using GSM voice and
to sabotage from a GSM Jammer which can bePSTN, however, both usually attract call charges.
used to prevent devices from connecting to theYou should check that the solutions provider
network.supports both client and server initiated remote
IP Networks (the Internet)programming connections to the panel.
Due to the widespread availability of the Internet,Some control panel manufacturers allow remote
a large number of consumers are turning to voiceprogramming over the Internet but this method is
over IP for voice service. For the continuity ofproprietary and restricted to their particular brand.
clear telephone calls from human to human it's aThe preferred universal method is to use an audio
simple case of unplugging your analogue telephoneconnection over the Internet from a solution that
handset from the PSTN line and plugging it into anincorporates a VoIP ATA as the primary
analogue terminal adapter to make and receivetransmission device. Such devices have the ability
calls over the Internet. The human ear is veryto reliably transmit alarm signals, allow operators
forgiving and even though delays and echo into have two way voice conversations and allow
voice conversations can sometimes beAlarm Companies to remotely program any make
off-putting, both parties are usually able toof alarm panel over the Internet.
understand each other.Summary
Unfortunately, this is not the case with alarmThe cost and availability of the various networks,
communications. Somewhere between convertingexisting equipment and infrastructure, insurance
analogue into digital, traveling over the wire andrequirements and other concerns may ultimately
converting digital back to analogue, things likedetermine which solutions you chose to migrate
noise and latency are introduced and along withfrom the analogue to digital world. My hope is that
other problems with VoIP networks, can causethis article has helped cover some of the more
alarm communications to fail.technical aspects of the decision making process
An in depth knowledge of alarm panel protocols,and makes your transition as smooth as possible.
alarm receivers and Internet protocols has made