Re: Streamdevice reads weird 1 byte null data

[Ralph Lange via Tech-talk <tech-talk at aps.anl.gov>]

On Wed, 20 Sept 2023 at 08:48, Zimoch Dirk via Tech-talk <tech-talk at aps.anl.gov> wrote:

When not done correctly, 2-wire RS485 is prone to "echos" of the command you
send. A correctly made transceiver should disable its input while sending, but I
have had problems with newer MOXA DA-662 (but not older ones) re-enabling the
receiver too early. If MOXA uses the same chip in your nport 6650, it may be
unsuitable for 2-wire mode. You may want to try with a serial server from
another vendor.

Also,

depending on line length and communication speed, proper termination may be crucial.

Cheers,
~Ralph