(AM), and has a greater reliable range than license-free radios operating in the CB or 49 MHz bands.Initially proposed by Radio Shack in 1994 for use by families, FRS has also seen significant adoption by business interests, as an unlicensed, low-cost alternative to the business band.FRS Two way 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 only if the power output is over FRS limits, up to GMRS 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. Though 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 channels; the GMRS stations may use up to 5 watts of power while the FRS stations are restricted to 0.5 watt. The use of duplex radio repeaters and interconnects to the telephone network are prohibited under FRS rules, unlike in GMRS, where repeaters but not telephone interconnect are permitted, and the Amateur Radio Service. FRS radios must use only permanently-attached antennas. This limitation intentionally restricts the range of communications, and promotes sharing of the available channels.Communication withTwo way radio FSR and GMRS..