ADAT is the abbreviation for Alesis Digital Audio Tape. The term has two meanings, one historical and one of current use.

1. The Historical Meaning: The Recorder 

Originally, ADAT referred to a line of 8-channel digital tape recorders (S-VHS), launched by the Alesis company in the early 90s. These machines were a revolution for home studios and project studios, making multitrack digital recording much more accessible. It was common to synchronize multiple units to record 16, 24, or more channels. 2. The Current Meaning: The Digital Connection Today, the use of the term "ADAT" almost always refers to the digital audio connection format that was popularized by these recorders, known as ADAT Lightpipe. It is a standard that uses a fiber optic cable (with a TOSLINK type connector) to transmit multiple channels of digital audio at once.

The most common standard transmits:

• 8 audio channels at up to 48 kHz.

• 4 channels at up to 96 kHz (using the S/MUX protocol).

• 2 channels at up to 192 kHz (S/MUX4).