This handy guide will help to explain what some terms used to describe two-way radios and their use actually mean.

CTCSS (Continuous Tone Controlled Squelch System)

A method of making most use of a given radio channel, where a group of radios are set to transmit an inaudible tone with every transmission, and at the same time to only receive messages with the same tone set.

It allows several groups of radio users to make use of the same channel without constantly hearing messages not intended for their group.

CTCSS codes are sometime referred to as “privacy codes” and also (somewhat inaccurately) as “sub channels”.

FCC (Federal Communications Commission)

The American government organisation that oversees and controls access to the radio airwaves. In the United Kingdom the same role is carried out by OFCOM.

FRS (Family Radio Service)

This is an American government standard for short-range UHF walkie-talkies that can be bought and used in the USA and Canada with no restriction and no licence required.

FRS radios have 14 channels, and use frequencies around 462 and 467MHz.

The use of FRS radios in the UK and Europe is not legal, although not uncommon, due to people purchasing American radios whilst on holidays and bringing them home, and also buying them online, without realising the legal issues involved.

GMRS (General Mobile Radio Service)

This is an American government standard for UHF walkie-talkies that can be bought and used in the USA and Canada with no restrictions, although a licence is supoosed to be obtained from the FCC.

Radios that combine the FRS (see above) and GMRS channels are widely sold. These have 22 channels in total. They use frequencies around 462 and 467MHz.

GMRS radios can have up to 5 watts power output, giving longer ranges than FRS radios. The use of FRS radios in the UK and Europe is not legal, although not uncommon, due to people purchasing American radios whilst on holidays and bringing them home, and also buying them online, without realising the legal issues involved.

IP (Ingress Protection)

Ratings These are an international standard series of protection levels against dirt, dust and liquids getting inside a piece of equipment. The first number relates to solid particle ingress protection, the second to liquid protection. The higher each number, the higher the level of protection provided.

Man-Down

A feature of some walkie-talkies, where a tilt-switch inside the radio automatically sends an alarm signal if the radio is tipped on its side for more than a preset period. The radio usually beeps to warn the user that the alarm signal will be sent if the radio is not positioned upright again.

The purpose of the “man down” feature is to protect lone workers, so that if someone was to fall, become ill, or be attacked, resulting in them falling down, their radio would send out an alarm signal that is picked up by someone in a control center or security office, who can then send help.

PMR446

This is a UK (and European Union) standard for basic, short-range radio that can be sold to and used by anyone without the need for any kind of radio licence. Radios that conform to this standard, whatever brand, all must have the same eight channels, and can have a maximum power output of 0.5 watts. They use eight frequencies in the UHF band, around 446MHz, hence the name. Different makes of PMR446 radios should be able to communicate with each other.