Datamax H-4212X Operator's Manual page 150

Communication Jumper locations:
+5 Volts Jumper location:
5. Slide the Main Board into the printer and secure it with the two previously removed
Screws.
6. Connect communication cables to the Main Board and plug in the power cord.
For RS-422/485 communications, ensure that
your cable meets the requirements for proper
data transfer (per the table, right).
140 H-Class