PL2303 HX rev D Communication very slow

I have a USB adapter Serie Model PL2303 HX rev D, and communication is very slow, about 6-8 seconds for a response following a requisition. I am a 9600 or 19200 baud, no difference. Try computer with win 7 32bit and also computer with win xp 32 bit, and no difference.
If you have an idea, it would be very appreciated.
Thank you


Thank you for contacting us about your serial adapter.

The serial adapter just acts as a conduit for the messages sent by the computer and the device at the other end, and will pass messages back and forth as fast as it receives them, within its maximum speed, which considerably higher than what you are seeing. I suspect in this case that the delay is in the response from the device at the other end of your adapter, especially since you are seeing the same results from more than one computer.

If you have a Plugable adapter, please contact us at, and we can do diagnostics to see if there might be something wrong with the drivers in the computer.

Thank you!

I’m going to close this thread. If you have any other questions or comments, please contact us directly at Thanks!

Ok, I wait for new parts,
Thank’s David