Na jednom ruskom forumu sam nasao ovo:
Na drugom sajtu sam nasao kako testirati serijsku vezu i adapter:
“Testing the RS232-to-TTL Adapter
Confirm that the RS232-to-TTL adapter is connected to the laptop, the power supply is connected to the RS232-to-TTL adapter. Turn on the power supply, and start your terminal program. Type a few letters. If you see the letters that you type, then you have your terminal program in "local echo" mode. Turn this feature off, otherwise you'll see double characters when talking to your hard drive.
Next, create a loopback connection on the adapter. All you need to do is connect the RX & TX pins of the adapter together.
Now if you type into your terminal program, you should see the characters being displayed. If not, then there's something wrong with your RS232-to-TTL adapter, and you should not proceed until you determine the problem and fix it.”
Kad pisem nesto u hyper terminalu, nista se ne pojavljuje, znaci da nesto nije u redu. U device manageru se normalno vidi com port, imam samo jedan.