FRS and GMRS radio walkie-talkies

General Mobile Radio Service, or GMRS, is a service where radios of fairly high-power can be purchased and used for hobby, personal, or business use.  The most popular type of GMRS radio on the market is the handie, also known as walkie-talkies and handie-talkies:

The difference between GMRS radios and Family Radio Service. or FRS radios is that GMRS radios have a higher output to reach further distances. The FRS radio on the other hand are limited in power output. GMRS handies are available with outputs anywhere from 1 watt to 5 watts output. FRS handies are limited to 500 mW, or half a watt.

In the USA you need a license from the FCC in order to use a GMRS radio. In Canada you do not need a license, however, output is limited to 2 watts instead of 5 watts.  For more FCC licensing info, go to the FCC GMRS home page.

it's interesting to note that the vast majority of Amateur (ham) radio handies also have a maximum output of 5 watts.  Anything more than this, and the batteries will drain very rapidly!

These radios all work in the UHF band. Specifically, from fixed channels in the 462 MHz to 467 MHz range.  They all use Narrow Band Frequency Modulation (NBFM).  Here is a frequency chart.

The FRS radios have eight channels and the GMRS radios have 15 channels; however, most GMRS handies you can buy today will be capable of operation on both GMRS and FRS, meaning that the handie will have a total of 22 channels.  Eight of those channels are FRS and will only be able to operate with 500 mW output. The remaining 15 channels are legal to use with up to 5 watts from your handie and up to 50 watts from a mobile or base.

GMRS was started up in the 1960s by the FCC who called it the class A citizens radio service. At this time radios were very expensive for the average consumer and the band was used mostly by businesses and industry. 

FRS was created in 1996 by the FCC as a low-cost, low-power, no licensing required alternative to the pricier GMRS radios.