I worked my way up from Administrator to Network Administrator for a small
company almost 20 years ago and tried out a "cardless" network to link 3
computers. It came with both serial and parallel port cables. The parallel
ones were much faster but of course that meant you couldn't attach a
printer - a major issue. The idea was a flop as it was much, much slower
than the slowest 10 base 2 coaxial cable Ethernet network. Even small file
transfers brought the systems to its knees for long periods.

When Ethernet cards came down to $150 each we upgraded and never looked
back. Windows for Workgroups provided the networking software.

But that would not be your situation, so it should be quite fast enough for
your needs. You will need some custom software which could be expensive.