Walkie-talkie

A walkie-talkie is a portable, bi-directional radio transciever, first developed for military use. Its major characteristics includes a half-duplex (only one can receive and transmit at a time) channel, and a push-to-talk switch that starts transmission. The typical physical format looks like a telephone handset, possibly slightly larger but still a single unit, with an antenna sticking out of the top.

The first radio receiver/transmitter to be nicknamed "Walkie-Talkie" is the Motorola SCR-300 created in 1940 by an engineering team at the Galvin Manufacturing Company consisting of Dan Noble, who conceived of the design using FM technology, Henryk Magnuski who is the principal RF engineer, Marion Bond, Lloyd Morris, and Bill Vogel. Motorola also produced the SCR-536 radio during the war, and it is called the "Handie-Talkie".

Al Gross also worked on the early technology behind the walkie-talkie between 1934 and 1941, and is sometimes said to have actually invented it.

During World War II, the United States and her allies used walkie-talkies as one of several different kind of communication devices to help front-line units to stay in close communication with each other, as well as with units in the rear.

Modern hand-held transceivers are valuable communication tools for police and emergency services, as well as industrial and commercial users, using frequencies assigned to these services.

Lower-powered versions are used as popular children's toys. Personal walkie-talkies are popularly used with the Family Radio Service or FRS. FRS works in the GMRS band which is also used for business walkie-talkies and mobile radios. Walkie-talkies are a useful communication tool for business and personal use.

In the series
Walkie-talkies are used in several episodes of the series, mainly by the prisoners to keep touch with either other during missions.