Dial Tone Definition

Central office (CO) dial tone, sometimes referred to as hard dial tone, is provided by the CO switch to a terminal device. When the dial tone is seized, the user is free to dial a telephone number. See also CO.

Stutter, or stuttered, dial tone is dial tone interrupted by short, regular periods of silence, and is used by some centrex and PBX systems as a message indicator, typically indicating that a voice message has been deposited in a voice mailbox either integrated with or interfaced directly to the system. Stuttered dial tone also is often used to confirm that a feature, such as call forwarding, has been activated or deactivated. See also call forwarding, centrex, and PBX.

Video dial tone, or visual dial tone, refers to the notion of a broadband network that provides videoconferencing capability on demand. See also broadband.