DIN sync

The DIN sync standard, often called "SYNC" or "Sync24" (more rarely "Sync48"), defines an interface for electronic music instruments.

It was introduced in the early 1980s by Roland Corporation for the synchronization of music sequencers, drum machines, arpeggiators and similar devices. It has since been superseded by MIDI, in the mid to late 1980s. The DIN sync standard consists of two signals, clock (tempo) and run/stop. Both signals are TTL compatible, meaning the low state is 0 V and the high state is about +5 V.

The clock signal is a low frequency pulse wave suggesting the tempo. Instead of measuring the waveform's frequency, the machine receiving the signal merely has to count the number of pulses to work out when to increment its position in the music. Roland equipment uses 24 pulses per quarter note (PPQN for short), known as Sync24. Therefore, a Roland compatible device playing sixteenth notes would have to advance to the next note every time it receives 6 pulses. Korg equipment uses 48 pulses per quarter note.

The run/stop signal shows whether the sequence is playing or not.

The DIN sync standard is so named because it uses 5 pin DIN connectors, the same as used for MIDI. DIN sync itself is not a DIN standard. Note that despite using the same connectors as MIDI, it uses different pins on these connectors (1, 2, and 3 rather than MIDI's 2, 4 and 5), so a cable made specifically for MIDI won't necessarily have the pins required for DIN sync physically connected via wires. In some applications the remaining pins (4 and 5) are used as "tap", "fill in" or "reset and start", but this differs from one device to another.

The layout is:

If a device is a DIN sync sender, the positive slope must reset the clock signal, and the clock signal must start with a delay of 9 ms.

A detailed description on how to implement a DIN sync sender with Play, Pause, Continue and Stop functionality was published by E-RM Erfindungsbuero.

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