Keyer

A keyer is a device for signaling by hand, by way of pressing one or more switches. Modern keyers typically have a large number of switches but not as many as a full-size keyboard; typically between four and fifty. A keyer differs from a keyboard in the sense that there is no "board"; the keys are arranged in a cluster. A keyer may take the form of a single telegraph key for keying Morse code. In this use, the term "to key" means to turn on and off a carrier wave, typically. For example, it is said that one "keys the transmitter" by interrupting some stage of amplification with a telegraph key.