Hi,

I need to communicate over tens of meters with several PICs (16f874) using
RS232. The idea is that all devices listen for their address and then accept
commands to recieve or send data packets. I am looking for a driver chip to
allow me to do this. Ideally the driver should be able to recieve data at
any time, but only turn on its output when data has to be sent by that
device. (avoiding bus contention)
Cost is an issue.
On a slightly OT note, does any one know how to use an MSComm control in
Visual Basic to send 9 bits of data? I was planning to use the 9 bit mode in
the PIC to distinguish between address and data.

Thanks for any help


Joe