I have a number of get console Airconsoles - these are nice, simple, small, and cheap terminal servers.
Unfortunately(?) I don't use them often enough to always remember how to connect to a specific serial port -- what is the ssh port offset? 3000? 4000? What if I have a firewall that only allows port 22?
This is my cheat-sheet:
Connecting to port 4:
ssh <ip> -p 4004