[geeks] Connecting two computers with serial cables - do you have to have two cables?

[Jonathan Groll]

I would like to connect two computers together by serial cable, since
these machines are running headless on my bookshelf, the idea behind
using the serial cables is to offer an emergency login prompt to each
machine should things go wrong. 

So each machine will be running a serial getty. The problem is that the
device is locked by the getty process (at least under linux), so trying
to launch minicom to see the other machine over the same cable results
in "/dev/ttyS0 is locked". Is it really necessary to have two cables to
connect two machines in this manner?

Thanks,
Jonathan.