> RC> null-modem, IPX over TCP/IP, as well as the IPX.COM TSR from Novell
 > RC> for their Ethernet cards).

 > This is the first I have heard of IPX.  I gather that I can use IPX
 > protocols (?) to write my program and test it down a null modem cable,
 > and when I get myself a couple of ethernet cards (a long way away) then
 > I can reuse old code?

Provided you isolate the communications side effectively in your code and
don't 'hardwire' things to the specific method being used, there's nothing
stopping you from doing this anyway.  Just create a "communications
API" for yourself and have nothing other than code within that API use
communications specific data structures and variables; for example, use
"start_link()", "end_link()",
"check_status()", "send_data()",
"receive_data()" as generic functions, and anything which uses
those doesn't concern itself with how the system does them. Rewriting or
replacing the communications portion becomes a lot easier as a result.

Using IPX as a starting point is probably not a good idea though as
documentation on using IPX can only be obtained from Novell, documentation
which costs a significant amount of $$$'s.

Besides, unless you're using Novell's IPX serial drivers (proprietary) IPX
over modem is a kludge. The communications channel goes through two
protocol stacks (IPX then IP) before getting to the serial layer. Needless
to say that this tends to be very slow.


  cheers,
  david

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