A professional who operates telegraphic typewriter to send and receive messages. Responsibilities include:

• Turns on machine and types identifying code for station called or acknowledges calls from other stations.
• Types outgoing messages when stations are connected.
• Reads incoming messages to detect errors and presses lever to stop transmission when messages are garbled or overlined.
• Types requests for clarification.
• Enters date, time, and serial number on messages sent and received.
• Pastes messages received on tape on paper forms.
• May type messages on tape attachment and transmit them by inserting tape into machine when stations are connected.
• May be designated according to system used as Multiplex-Machine Operator.
• Important variations are kinds (trade names) of telegraphic typewriters operated.