Logic controller connection cable

I have crouzet millenium 3 logic controller, that needs to be connected to the USB or serial port of the PC. The simple cable costs more than 60 euros. Can an electronic expert suggest me a possible pin-out configuration of the 6 pin plug on the PCB of the controller. The 6 pin plug can take either a USB or a Serial (9 pin) port connection from PC. The controller has a ATME GA128 CHIP.

I can see pin-1 going to ground and pin-2 going under a TTE 8pin IC, pin-3 passing through a resistor (number on it 682) to the TTE IC, pin-4 going under the main chip, pin-5 passing through resistors to the main chip, pin 6 passing through a capacitor (I think) to the ground.

any ideas? If you don't know about this controller then, please advice me with a possible pin-out configuration.

Thanks