Transmitter - Legal Restrictions

Legal Restrictions

In most parts of the world, use of transmitters is strictly controlled by law because of the potential for dangerous interference with other radio transmissions (for example to emergency communications). Transmitters must be licensed by governments, under a variety of license classes depending on use: (broadcast, marine radio, Airband, Amateur etc.), and are restricted to certain frequencies and power levels. In some classes each transmitter is given a unique call sign consisting of a string of letters and numbers which must be used as an identifier in transmissions. The operator of the transmitter usually must hold a government license, such as a general radiotelephone operator license, which is obtained by passing a test demonstrating adequate technical and legal knowledge of safe radio operation.

An exception is made allowing the unlicensed use of low-power short-range transmitters in devices such as wireless microphones, cordless telephones, walkie-talkies, Wifi and Bluetooth, garage door openers, and baby monitors. In the US, these fall under Part 15 of the Federal Communications Commission (FCC) regulations. Although they can be operated without a license, these devices still generally must be type-approved before sale.