Hello teh,
I dont understand what you need, you need the cable for OP3 or OP17?
For OP3 you will need a special cable with a 9pin to RJ45 plug for PC configuration download, but is included when you purchase the OP3.
For OP17 you need a cable with 9 pin to 15pin plug and the pinout is described in the manual.
i dont know the manual reference, but is available in the site.
Hope this help,