Sender

A sender was a circuit in a 20th-century electromechanical telephone exchange which sent telephone numbers and other information to another exchange. In some American exchange designs, for example 1XB switch the same term was also used to refer to the circuit that received this information. The corresponding device in the British director telephone system was called a "director" and, in other contexts, "register".

A secondary meaning within the UK broadcast engineering community is as a synonym for broadcast transmitter.