The Family Radio Service is a ‘licensed by rule’ service, under Title 47 Code of Federal Regulations (CRF) Part 95 subsection B. Licensed by rule means that the rules permit the use, a FCC license is not required.
Use
Primarily for short distance communications between individuals. (a) Digital data May also transmit digital data containing location information between one or more FRS or GMRS units. There are some GPS devices, such as the Garmin Rino series, that use FRS & GMRS frequencies to transmit location data between devices.
§95.531 Permissible FRS uses
Frequencies
Frequencies for the FRS radios are shared with the GMRS service. Most radios designed for FRS use do not list the frequency, but display a channel number.
Power
Depending on the device you are looking at for FRS radios they list anywhere from 2-5 miles as their range. However power is limited to 2 watts and some channels are limited to 0.5 watts (there are repeater output frequencies for GMRS).
A table of FRS/GMRS frequencies, power and bandwidth settings can be found here.
Older FRS Radios (pre-2017)
The FCC rules for Personal Radio Services were updated in 2017. Prior to that time there were some frequencies (channels) that were unique to the FRS and some that were shared with the GMRS. Also prior to 2017 the FRS radios were restricted to 0.5 watts on all channels. There are still a large number of these older radios around.
Privacy Code
In the pre-2017 FRS radios some manufacturers listed “privacy code.” These are in fact sub-audible tones (CTCSS for those familiar with ham pl tones or DCS for the digital version). All they do is prevent you hearing anyone else on the same frequency unless they are using the same tone. So there is NO privacy on the channel.
Most manufacturers just list a number for the privacy code, not the actual CTCSS or DCS tone. You will usually find them in the documents with the radio or on the manufacturers web site.
“Extra” Channels
Some FRS (and GMRS) radios list “extra” channels, most notably the Midland brand. A list of the Midland “privacy” and “extra” channels can be found on the communications resource page.
Final Thoughts
FRS radios are really only useful for short range communications. Despite what the packages and marketing suggests you will be unlikely to get 2 miles out of most of the radios. The new FCC rules require the radios to have a fixed antenna, and without getting an antenna higher you will be limited to almost real line of sight. Practically do not expect to get more than 1/2 mile out of these radios.