DIN sync

pin out

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

Definition and history

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 It has since been superseded by MIDI, in the mid to late 1980s.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 lead 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 even used as "tap", "fill in" or "reset and start", but this differs from one device to another.

The layout is:

• Pin 1 = start / stop (stop = 0 volt, start = +5 volt)
• Pin 2 = ground
• Pin 3 = clock (symmetric pulse wave 0/+5 volt, the positive slope determines the clock step)
• Pin 4 = reset start (optional; technically the same as start/stop; the reset is valid for the song mode of roland machines)
• Pin 5 = fill in (optional; technically the same as start/stop; it activated the fill in function of the TR-808 and TR-606)

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.^[1]

Relation to other clock systems

other clock systems

The MIDI interface uses the same connectors, but is electrically not compatible with DIN sync. The MIDI protocol contains MIDI clock (also known as MIDI beat clock). MIDI clock also works with 24 so called "ticks" per quarte note (one tick corresponds to one nibble of the protocol).

So called "analog clock signals" are equivalent to the clock signal at pin 3 of DIN sync interface. The clock rate is usually higher than the DIN syncs rat. Typical values are 48, 96 or 192 pulses per quarter note (examples: Oberheim DMX, DX, DSX; Linndrum 1 and 2).

So called "analog trigger signals" transfer a pulse per musical event. For instance a trigger correspongs to a step of an analog sequencer or an arpeggiator, a step in a rhythm pattern. Typical analog triggers run at four pulses per quarter note.

combining DIN sync with other clock systems

The combination of DIN sync with a different clock system can be achieved either by converting the format and / or the clock rate (see list below) or by using a central unit (so called master clock), which provides multiple clock formats. The approach with an masterclock is usually chosen, if a synchronization with absolute time is required, like synchronisation with a tape recorder of with video.

Typical devices which can act as master clock and provide a DIN sync are: Roland SBX80, SBX10; Friendchip SRC; Yamaha MSS1. Many drum machines, which have DIN sync and MIDI Clock outputs can act as master clock for those two formats.

converting DIN sync from and to other clock systems

Though DIN sync and MIDI clock have the same clock rate, they require a conversion of the format within a micro processor or similar. The conversion from MIDI clock to DIN sync is available in many industrial devices. For the conversion from DIN sync to MIDI clock there is at the moment only the device 'Sync-Split2' of the company Innerclock Systems. Also two no longer produced devices do this type of conversion: Roland SBX10, Korg KMS30.

To get an analog trigger or clock from the DIN syncs clock signal one has to use digital frequency division or frequency multiplication. There are no dedicated industrial devices, which provide a division. The Roland SBX10 can convert into a 48, 96, and 120 PPQN clock.

Devices with DIN sync

Some devices have a DIN sync input as well as DIN sync output, other device hav only a single DIN socket which sometimes can be switched between input and output.

[please complete this list]

See also

• MIDI beat clock
• MIDI timecode

External links

• Doepfer general FAQ: Sync specification
• Philip Rees MDS
• Sync Unit DC - freeware DIN Sync generator
• ByteNoise: DIN sync

References