Thanks again for your answer.
I've read in a long time that forum. From what I have seen the cable with the yellow line is for models II and III, and what you got, that is all black, to be the oldest for model I.
But to be sure you should be tested with DB.
Because the DB that i bought "wearing" adapter mount Hasselblad "H" I'm trying to find the adapter from "H" to GX680 I.
If I find Adapter, then with a pc sync cable theoretically would be able to work but i will not have real tethered!
If you have a way to test the cable with a Imacon DB and a GX680 I, gladly I can buy the adapter and the cable.