I just bought a used TX-870 register, but I can't connect it with my pc. always time out error

the pc is an old laptop with a RS232 serial port in it. male port. the operation system is window xp but non-english version. I set up the port in device manager following the PLM version 3.11 help. (port 1, 38400, 8, none, 1) and set up them well in PLM Network Comm Port Setting as well.
the communication part of ECR is the same as required.

I used the dealer made and tested serial cable to connect PC and ECR but unfortunatelly not working. Looks like my pc didn't find the cash register.
Is there any other thing I need to set up in the SP position?

Any one can give me a helping hand? Thanks you so so much.