PC - MDC2460 RS232 COMM İSSUE

Hello,

I am new in roboteq controllers and I have MDC2460 2 channel controller .. I wanna use it with commands via rs232 pins on 15pin I/O connector 2(tx) 3(rx) and 5 (gnd).. I have connected them to PC via s-link usb-rs232 converter (db-9 as 2(rx) 3(tx) 5(gnd)) and I started to listen the port from realterm terminal but there was nothing .. I can communicate with usb and I can listen it from serial terminal but I wanna communicate with rs232 ..is there any config for this?