Hi Uk,
thank's for the replay. I tried all sort of ways using unblocking reads, but to no avail. I could not get a real satisfactory bidirectional communication. If you know an example where this works, I would be gratful.
I now resort to a rather clumsy way, by opening two ports, using one to send, the other to receive. This works, but it does not seem to be too clever and if there is a better way, I am happy to engulf it.
cheers, Daniel