qtalk VS "echo & cat"

We’re having serial communication problem between QNX 6.2 and our hardware device (RF Generator). When we try to use “echo” to send commands to the RF and read the responds using “cat”, we will get some non-printable characters occasionally. However, when we use “qtalk -m > /dev/serX”, we have no problem at all, does anyone know if there’s any flow control done by qtalk internally? The RF generator doesn’t support software or hardware flow control at all.


stty -a < /dev/serX
should show you the port attributes before and during qtalk.

My guess is since you are not using flow control, qtalk may work better because you are typing/transmitting one character at a time, while with echo, you are dump a string all at once. Try:
echo a
sleep 1
echo b
sleep 1

and see if it works better :slight_smile: