Bruce, this is terrible
We pray that everything will be right for you.
Let me know if we can help you something!

I think this is the best place to put this.

http://www.symbos.de/appinfo.htm?00027

It can be that these drivers and sources can be tailored to make EPNet  and Simbiface3 NET drivers for SymbOS.

EPNet ones can be easier, because the chip used on the EP card is an evolution of the Wiznet W5100, already used on two of the MSX net cards.

Don't think that Jörn(Prodatron) is concentrated on SF3 development..... Hans(TMTLogic) is always waiting him to appear and finish the necessary SymbOS drivers.

I think that better we aid ourselves, or this development can last decades.... 

Yes the W5300 and W5100 are very similar, but the W5300 is a 16-bit device. You can read/write the high and low bytes separately, but you always have to read/write 2 bytes, even when you only want one byte eg the last byte of a packet . It leads to complications in the code and bugs !

The W5300 is higher performance and has more RAM, but I think the limiting factor for performance is probably the z80!