I tested with our Auto485 adapter in Auto mode. No problem communicating using the VB6 sample program if you remember to change the baud rate to 38400 bps (default is 9600 bps) first before openning the port. However, when Auto485 is put in the RTS-controlled mode, VB6 sample program does not work.
I then tested communication using TLServer and found out that TLServer will work with Auto485 in both Auto and RTS-controlled mode. This is because TLServer program controls the RTS signal before and after transmission. But the simple "MSComm1.Output" function provided by VB6 controls does not have the same feature.
You may want to check with the online community whether someone has written a Visual Basic comm program that controls the RTS signal durng transmission, or give Bill Gates a call - just kidding