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Re: USB "null modem" cables and related Linux driver questions

> If none of that are options, you can resort to using an "ethernet
> dongle" on both sides and an ethernet cable between the two.

[ If one of the two computers has a free ethernet port, you can of
  course also such a dongle on the other computer.  ]

BTW, those ethernet dongles can be found pretty cheaply (like $10 or
less) and they can be handy in many cases to add an ethernet port (or
several ports, even).  IOW, it's a good tool to have in your box.