Ok picture is getting clearer now. The QNX machine has a card that uses RF-Cable to connect to the CM and that card comes with a driver made by Broadcom (or who ever). When you start the driver it creates /dev/bcmnet_fd?
I understand now. I beleive the broadcom driver is a network driver that let Net.fd connect to it and not a driver that connects to Net. This is just an assumption, this needs to be confirm with the people responsible for that driver.
You should be able to use it with Net.fd just like if it was a serial port. Check Net.fd documentation. The sequence to support it would look like:
broadcomdriver (what ever its name is ) &
Voila! You may have to specify option -a, -c, -b to Net.fd depending on how the broadcom driver is design. Note -b is an undocumented option…
At this point QNX is able to use the boardcom driver just like if it would be a standard network driver. This can actually cause some unwanted side effect. QNX may decide to send packet on it’s own on the RF-cable, which I beleive you want to avoid. You have to make sure there is no entry in the netmap database about the broadcom card. You also have to make sure TCP/IP is not started, otherwse the TCP/IP stack may send data on that interface, which I don’t think would be good in your case.
The next step is to write a netraw program that binds with all the network cards (ethernet and broadcom) and with all the ethernet protocols type. The fact that the broadcom driver is accessed via Net.fd is totaly transparent to Net and to any program using the netraw interface.
You will probably have to set the ethernet driver to Promiscuous mode to be able to receive packet with ANY destination MAC addresses (typicaly network card reject packet that don’t have the proper destination MAC address).
Does that answer your questions?