Michal:
It's a basic 3 wire serial cable. Pin 2, 3 and 5. Straight thru from DCX to your serial port, or in my case usb to serial adapter on the laptop( eg. pin 2 - 2, 3 - 3, 5- 5). I cut an xlr mike cable in half and used the male xlr end to connect to the DCX 9-pin adapter. Dcx end pin 2<<->> 2 xlr , dcx 3<<->> 3 xlr, dcx 5<<->> 1 xlr. See the hopefully attached picture.
This end will plug into the snake , just like a mic. The female xlr end is wired the same. Mine works on a 100ft snake with no problems.
Good luck!