DIN Sync (also referred to as Sync 24)is a pre-MIDI synchronization scheme used most notably on Roland drum machines (including the TR-606, TR-808, TR-909, TB-303, and MC-202) and synths. This format is called “DIN” Sync because it employed a 5-pin DIN connector – the same one later adopted for MIDI. Pin one transmits 0-volt “stop”and 5-volt “Start/continue” messages, while pin three transmits 5-volt timing pulses at a rate of 24 PPQN.
NOTE: although the sockets are the same, NEVER attempt to connect MIDI gear to DIN Sync gear. Bad things will happen. A few other manufacturers adopted DIN Sync but it has been largely superseded by the development of MIDI.