A cue tone is a message consisting of audio

Audio frequency

An audio frequency or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human...

 tone

Pitch (music)

Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

s, used to prompt an action.

In broadcast network

Broadcast network

A broadcast network is an organization, such as a corporation or other voluntary association, that provides live television or recorded content, such as movies, newscasts, sports, Public affairs programming, and other television programs for broadcast over a group of radio stations or television...

s, a DTMF cue tone or subaudible tone

Subaudible tone

For the use of subaudible tones in Two-way radio see: CTCSSA subaudible tone is a tone that is used to trigger an automated event at a radio station. A subaudible tone is not inaudible; however, it is usually at a low level that is not noticeable to the average listener at normal volumes...

 is often used to prompt insertion

Local insertion

In broadcasting, local insertion is the act or capability of a broadcast television station, radio station, or cable TV system to insert or replace part of a broadcast network feed with content unique to the local station or system...

 of a local TV commercial or radio advertisement by the broadcast automation

Broadcast automation

Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator...

 equipment at the broadcast station

Broadcasting

Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...

 or cable headend.

Cue tones were also used on broadcast carts (cartridge tape

Magnetic tape

Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...

s) to cue local equipment to start and stop, particularly to cue the tape player itself, as the tape runs in an endless loop

Endless Loop

Endless Loop is overall, the fifth EP by Japanese singer Eiko Shimamiya but this is her second EP produced by both I've Sound and Geneon Entertainment. It was released on December 14, 2005...

 and often contains several segments of content.