Originally Posted by cjwood555
The main issue with some cheap ones is a lack of hardware buffers (important for large data transfers / streams). Some of them don't even implement the handshaking lines.
Chris
The biggest problem with most USB to serial adaptors is they can only use the standard baud rates (speed of data transfer) that VAGCOM rarely uses for most cars and use one that is "near enough" which makes them unreliable or not work at all.