Home wireless intercoms are transmitter and
receiver sets that use home AC wiring for two purposes. First, they derive power for the
units from the AC current. Second, they use the same AC wiring as a form of antenna to
transmit and receive the signals from one unit to another. This is called "carrier
Many wireless intercom owners may not know
that their intercom broadcasts beyond the limits of their home. The signals can be picked
up accidentally or deliberately by anyone nearby who has a wireless intercom operating on
the same frequency or anyone with a frequency scanner looking for that type of emission.
Moreover, the carrier current signals can be carried over great distances by wire. The
power companies use the same carrier current technology to obtain information that allows
them to operate "load management" or "kilowatchers" systems to manage
the power to large groups of homes.
Baby monitors also amount to self-installed
bugging devices that transmit signals well outside the confines of the home where they are
placed. Some are hooked into the homes AC wiring and use the same carrier current
technology discussed above. Others transmit on common radio frequencies. The baby monitors
are very effective in alerting parents to crying or other sounds in another part of their
home. They provide peace of mind for new parents, but the potential privacy issues need to
Many hotels and motels offer a version of the baby monitor to
guests who wish to use the club or guest services, while still minding the toddlers asleep
in their hotel room. This service is an integral part of the hospitality features
incorporated into the hotel phone system. That means it is possible from a central
location to activate the microphone within the telephone set within any room at any time.
Consider the implications of this built-in surveillance system for government or business
employees who think they can have confidential discussions in their hotel room.
Paul F. Barry & Charles L. Wilkinson (Trident Data Systems),
"Invasion of Privacy and 90s Technologies," Security Awareness Bulletin, No.
2-96. Richmond, VA: Department of Defense Security Institute, August 1996.