Modbus connection details

Sir
My requirment is checking the modbus data through rs232 serial communication from slave device AZL siemens PLC.now i connected both end by RJ45 connection for checking purpose and pin details are mentioned below but communication is transmitting from master end but no reply.parameters and address are same.
ABB CI853 master AZL slave
3---TxD ---------->-------------------------3--RxD
5---GND -----------<>----------------------4- GND
6---RxD ----------<-------------------------1- TxD