Network hub: A network hub is a network device that a single network of the same media types. but paths are intermingled (obsolete)
Network switch: A network switch is a network device that a single network of the same media types. but paths are separated.
Network bridge: A network bridge is a network device that connects a single or multiple network segments of different media types.
Network router: A network router is a network device that connects multiple network segments of the same media types.
Now to get confusing. Many network devices can be a combination of the above. Take for instance what a lot of people call a router is actually a combination of of a bridge and a router.
These we all pretty much know about, but what if we wanted to connect some legacy devices such as dumb terminals so they would have virtual access to the network. Actually they are just acting as an extra keyboard and screen for the host system.
Now you have turned one system into four systems. Everything would pretty much be in the text only mode, but there are a host of programs available for this type of access. Those older systems could be put back to use in a pinch.
- Links2, lynx, elinks – internet
- Bashpodder – audio podcast collector
- Alpine – email client
- Irssi – inter relay chat
- Centerim – instant messaging client
- Oleo or Sc – spreadsheet
- Vim, emacs, nani, joe, or a dozen other programs – word processing
- Antiword – deals with office based documents
- Putty – secure accessing tool
- Screen -multiple seesion tool
- Ledger – accounting (seems to be based on gnucash)
- gpm, mc, synaptic, sed, awk, sort, ncurses, bash ,ssh, wget, curl
- Sqllite, mysql, psql, plus man other – databases
- Hnb – outliner to organize ideas
- freebasic, gcc, python, pgp, pgp-cli, perl and etc programming language tools.
- Too many to list here – games. (i.e ninvaders)
- Moc, aplay, mplayer, cmis and may others – music players
- Espeak or Festival – voice synthesizer.
- Nget and may others – news readers.
- Cdrecord – cd buring program.
- wird – nice calendar tool.
Just think a Sega Dreamcast running netbsd could be a computer terminal.
You can get some rs232 to ethernet devices specific for this task, but for the price, you are better off getting a Raspberry Pi or the like Unless you want to use an old computer. More ore information on interfacing at: http://www.instructables.com/id/Direct-connecting-two-old-fashioned-modems-or-te/
I am sure you could do this with Microsoft Windows, but have not tried it.