In telegraphy communications, a device with a finger-operated lever with contacts that make and break a circuit to send characters by means of dots and dashes or spaced clicks.

• 在电报通信技术中,一种用手指操纵的器件,通过按下、松开使电路一会儿通、一会儿断,形成点、划、空的信号,从而发送出字符(信息)。