1xMaster to 3xSlaves for Game Boy using LSDj
This acts same as a modified DMG-07 unit, just with GBC cable ends. It lets you sync one master to three slaves from LSDj. It is also tested with Arduinoboy.
GBC cable end (Works with DMG cables too, but it might get crowded if inserted in neighboring connectors!), so use dual head cables for DMG usage.
Syncing multiple Game Boy's to DAW with Arduinoboy: