A term coined by Digidesign in the early days of Pro Tools. Pro Tools has always operated at an internal timing resolution of 256x the sample rate. In order for multiple audio interfaces to be able to remain locked together in a system it was necessary to carry this clocking information between the interfaces themselves. It couldn’t just be passed through the multi-pin cable that connects them to the host cards for various technical reasons. So Digidesign decided to use a BNC connector (they were easily available and good for the job) to transfer this high resolution clock data, but to keep people from getting confused and thinking it was a standard word clock connection, Digidesign came up with the term Superclock and labeled them as such. Any device, such as a synchronizer, that connects to a Digidesign system and needs to accurately control its clock must output this superclock reference.