One of the most useful intercom systems available
is an outdoor intercom. These intercoms are used at outside entrances to
buildings, security gates, or anywhere anyone may need to communicate
with a person inside a building or at a remote location. They save
people from having to make trips to your entrance door to let people in,
and they alert you when customers or visitors are at a locked security
The first decision you need to make on choosing an
outdoor intercom is whether you want a wired or wireless solution. A
wireless system has the advantage of ease of installation, but there is
always a possibility of interference. You seldom have to worry about
interference with a wired system, but there's the expense of installing
the wire. Both types of outdoor intercoms will be discussed here.
Wired Outdoor Intercom
Just like it sounds, a wired outdoor intercom has
wires running between the outdoor speaker and the indoor units it is
connected to. Usually the cable used is a two-conductor, shielded wire,
but could be a computer network type CAT-5 cable depending on the type
of intercom system. The shield on the two-conductor wire helps the wire
resist picking up electrical interference from other electrical devices
that could produce a buzz or hum on the intercom system. CAT-5 systems
are usually digital devices so they do not have this problem.
The two-conductor systems are used for both
commercial and residential properties. These systems generally comprise
of two main components. The first is known as the "door station" and is
fitted outside the entrance to the building The second component is
called the "master station" and this is fitted inside the property.
Depending upon the size and general layout of the property it may be
more convenient or practical to have more than one master station.
The two-conductor systems are usually simple
systems that allow communication between the outdoor door substation and
a master station on the inside. If additional master stations are needed
inside, then a multi-conductor cable with as many as 20 wires is run
between the master stations.
With these systems, when a visitor arrives at the
door they press a button on the door station and this triggers a short
tone at the master station(s). Someone inside the property then answers
this tone and the two parties are able to communicate with one another.
The person at the door can communicate without pushing a button and the
person at the master station has to push a button. An additional
feature of these systems is a door release system which enables the door
to be opened remotely by the person operating the master station.
While two-conductor systems require multi-cable
wire between master stations, the CAT-5 systems use the same cable no
matter how many stations are required on the inside, but these systems
are typically more expensive to purchase.
Wireless Outdoor Intercom
When you need to communicate with people who are at
an outdoor location and you can't run wires to that location, an outdoor
wireless intercom is the solution. These outside wireless intercoms
communicate to an inside station or portable handheld two way radio via
radio waves. So wireless outdoor intercoms not only have the benefit of
not requiring installation of cable, they also allow for mobility of the
person or people monitoring the outdoor wireless intercom.
There are several varieties of these outdoor
wireless intercoms available. You can get heavy duty, tamper resistant
devices that communicate over long range, or lighter duty devices that
communicate a few hundred feet. Some devices communicate using a
proprietary method that only allows devices from the same manufacturer
to talk to each other, while others are more open and allow mixing
devices from different manufacturers. If you have existing two-way
radios you use, you may be able to get outdoor wireless intercoms that
talk to them.
outdoor intercom system available is the Compact Wireless. This isystem will communicate with
other devices in the MURS wireless intercom product line. It has a range of up to 1 milet, but with obstructions in between range will be less. These outdoor intercoms work in walkie talkie fashion
where a button push is required to talk.
Outdoor Callbox Intercom
If you need a more heavy-duty
outdoor intercom, then a wireless callbox like the MURS Callbox XT
Outdoor Intercom may fit your application.
callbox is a heavy duty, weather and vandal
resistant wireless system that provides easy communication between the
callbox at a specific fixed location, and a base station intercom or
handheld two-way radio device. It allows for long range communication
between the devices over a distance of up to one-mile. This distance
can be increased with the addition of an external antenna. These
systems have become very popular for businesses where reliable and easy
to operate two-way communication must be available at all times.
Wireless callboxes use UHF and VHF frequencies to
communicate. Some of the wireless frequencies require an FCC License,
but there are five MURS radio frequencies that are unlicensed and very
MURS stands for Multi-Use Radio Service. This is a
newly created service for use in the United States and some Caribbean
countries. It is a low power, short range service in the VHF (Very High
Frequency) 150 MHz radio spectrum.
MURS radios have a power increase of four times
that of the Family Radio System (FRS) radios that are so common. And
unlike FRS, you can add a larger or external antenna to improve range.
If you want to put an antenna on top of your building, you can do it
with MURS. Some antenna manufacturers claim an external antenna can
increase the effective radiated power of a transmitter by a factor of 4.
Some MURS Radios can transmit up to four miles, and perhaps more with an
If your application requires unlocking a gate or
door from a remote location, then a callbox such as the MURS Callbox XT
Outdoor Intercom with Gate Relay is what you need. This call box has a
relay that can be controlled by pressing a button on a wireless intercom
like the MURS Commercial Intercom or any two way radio with the 2-tone
The MURS Callbox with Gate Relay also has a Sensor
Input that allows it to also operate as a motion, gate entry, tamper or
vehicle detection device. It will send a tone alert when optional
switch/sensor status changes. The Callbox will send a warning tone when
a change in the Sensor Input is detected. The Sensor Input will respond
to an OPEN or CLOSED switch.
Choosing the right outdoor intercom for you depends
on your application and your budget, but you can almost always find one
that will work for you.