Push-to-type operation: In telegraph or data transmission

Data transmission

Data transmission, digital transmission, or digital communications is the physical transfer of data over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media...

 systems, that method of communication in which the operator at a station must keep a switch

Switch

In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....

 operated in order to send messages.

Push-to-type operation is used in radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

 systems where the same frequency

Frequency

Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

 is employed for transmission and reception.

Push-to-type operation is a derivative form of transmission and may be used in simplex, half-duplex, or duplex operation

Duplex (telecommunications)

A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....

. Synonym press-to-type operation.

This is similar to Push-to-talk operation for radio phone communications.