IF PC link PLC ,What kind of cable we need?

IF PC link PLC ,What kind of cable I need?
I have a old Omron PLC C28p,What kind of cable I need ?
Someone told me I need a 15pins cable and a inverter which I don't know the name but it is quite expensive.
If it doesn't need the inverter then we also can PC communicate with PLC?

The C28P does not have a built in serial port. You need a Hostlink adapter to plug to the front of the PLC. The part number is 3G2C7-LK201-EV1.
Here is a link to the dip switch settings and the cable necessary to connect the hostlink to the computer.
3G2C7-LK201-EV1 Settings and Cable @ MrPLC.com

If you need to buy 3G2C7-LK201-EV1 you better cheak to buy new PLC.
It not cheap part as new(if you found one).
Try e-bay.com or plccenter.com