Re: USB to Serial
If the the MAX232 is actually connected as shown in your circuit, it won't work, cause the voltage doubler capacitors are replaced by shorts. No idea, if the device would bear it for longer time without permanent damage. I suggest, to use the circuit given in the datasheet!
If the circuit would be correct unlike the drawing, you should be able to communicate at least through Hyperterminal. With wrong MAX232 wiring, it could be that operation depends on RS232 driver strength, which could be different with USB adapter. However, any problems of this kind would reveal by checking the RxD and TxD lines for correct level.