Oki ES3640E User Manual page 54

When connecting multiple printer units of the same type,
they appear as *****, ***** (2), ***** (3), etc. These
numbers depend on the order of connecting or turning on
each printer unit.
> Ethernet – For network cable connection.
NOTE
Interface cables are not supplied with your printer unit.
C
ONNECTING THE PARALLEL INTERFACE
1. Turn off the printer unit and the computer.
2. Connect a parallel cable between the printer unit and
computer.
3. Turn on the printer unit and then the computer.
ES3640e MFP User's Guide> 54