The Family Radio Service (FRS) is
an improved
walkie talkie radio system authorized in the
United States since 1996. This personal radio service uses
channelized frequencies in the
ultra high frequency (UHF) band. It does not suffer the interference
effects found on
citizens' band (CB) at 27
MHz, or the 49 MHz band also used by
cordless phones, toys, and baby monitors. FRS uses
frequency modulation (FM) instead of
amplitude modulation (AM). Since the UHF band has different
radio propagation characteristics, short range use of FRS may be
more reliable than license-free radios operating in the
HF CB band.
FRS radios are limited to 500
milliwatts in the U.S., according to
FCC
regulations.
Channels 1 to 7 are shared with low-power interstitial
channels of GMRS, the
General Mobile Radio Service. A
license is required for those channels if the power output
is over FRS limits.
Unlike Citizens' Band (CB) radios, FRS radios frequently have
provisions for using sub-audible tone
squelch (CTCSS
and DCS) codes, filtering out unwanted chatter from other users
on the same frequency. Although these codes are sometimes called
"privacy codes" or "private line codes" (PL codes), they offer
no protection from eavesdropping and are only intended to help
share busy channels. Tone codes also do nothing to prevent
desired transmissions from being swamped by stronger signals
having a different code.
FRS stations on channels 1 through 7 may communicate with GMRS
stations on those shared channels; the GMRS stations may use up
to 5 watts of power, while the FRS stations are restricted to
0.5 watts.
The use of duplex
radio repeaters and interconnects to the
telephone network are prohibited under FRS rules, unlike
GMRS which allows repeaters,
