A serial null modem cable will work for both SLIP and PPP. Again, you
will need two DB-25 connectors. This time your cable requires only
eight conductors.
You may have seen other NULL modem cable designs, but this one allows you
to use hardware flow control—which is far superior to XON/XOFF
flow control—or none at all. The conductor configuration is
shown in Figure B-2:
Again, if you have a shield, you should connect it to the first pin at one
end only.
