Word clock is a time base reference only, providing a measurement of the passage of time and the speed at which samples should go by. Word clock carries no address or timecode information; therefore word clock by itself is not enough to sync two devices.

Some devices that use word clock include digital mixers, stand-alone hard disk recorders, computer-based digital audio workstations and computer audio cards.

When doing digital transfers between two different digital devices, some devices require word clock to be sent from one to the other. Two digital audio devices, such as a 2408 and a digital mixer must be connected via word clock cables to be synchronized to the same rate of digital audio, for playback to be consistent. The combination of SMPTE (address) and word clock (rate) is a complete sync scenario.