Lets build a simple 2 device LocalTalk network
You can network any Macintosh that has a Printer port (aka LocalTalk port). The Mac 512Ke & Plus are used as an example.
or 
Using an LocalTalk connector Using a printer cable
More flexible to add on later Cheaper
We will need:
2 Macs
2 LocalTalk connectors with 1 phone wire
(Note: Apple's brand name AppleTalk connectors are self-terminating. There were part of the AppleTalk Personal Network)
or
1 Printer cable (standard printer/modem cable)
This will accomplish:
Allow all Macs to share files using a peer-to-peer network software.
Recommendations:
If you will be using a printer cable with any 512K or 512Ke; my advice is to spend a bit more and use the LocalTalk connectors. They are easier to find and to add on to in the future.
If you want to share files:
One of the Macs needs to be a Mac Plus or higher running System 7.0 or higher.
One of the Macs needs to run an very old version of AppleShare file serving software.
- Or a current Macintosh needs to run a current version of AppleShare.
How to do it:
LocalTalk
1.) Take the LocalTalk connectors and plug them into each Mac's printer port
* The Mac 512K and 512Ke take a DB-9 connector, all other Macs use a Mini-Din 8 connector. The Mac 128K cannot be networked.
2.) Connect the LocalTalk connectors with phone wire.
Each connector will daisy-chain to the next connector.
Terminate each end of the network. They will have a switch or a phone plug type of terminator.
(In the example above, the red line on the Mac Plus' LocalTalk connector and on the
Mac 512K's LocalTalk connector are the terminators.)
* Do not make a loop, this will cause interference.
3.) Load the networking software on each Mac
A Mac 512K and a Mac Plus connected:


Printer Cable
1.) Plug printer cable into each Mac's printer port.
* The Mac 512K and 512Ke take a DB-9 connector, all other Macs use a Mini-Din 8 connector. The Mac 128K cannot be networked.
2.) Load the networking software on each Mac.
Two different LcoalTalk (PhoneNet) connectors:

Top- Plugs into a DB-9 printer port
Uses the phone plug as the terminator
Bottom- Plugs into a Mini-Din 8 printer port
Uses the switch on the side as the terminator
Plus it has two red LEDs which blink as data flows through it
Miscellaneous:
To add a serial printer (a printer with no AppleTalk capability) is easy.
1.) Attach the printer to 1 of the Mac's Modem port.
2.) Set up the appropriate software to share the printer on the network.
See your printer manual or contact the manufacturer.
** Don't forget - The total length of the PhoneNET wires is
Daisy chained - 1,800 feet / 550 meters with 24 Macs.
BackBone - 4,500 feet / 1,372 meters with any number of Macs.
The Mac 512 is a gYounk design & programmed site.