The PL522/523 ECM is configured with CAT ET using the following communications interfaces:
The 171-4400 Communication Adapter Gp or 317-7484 Communication Adapter Gp is connected between the
machine service connector and the PC serial port or parallel port. The CAT ET "Communications Interface
Device" is configured for "Caterpillar Communications Adapter II (RP1210)" or "Caterpillar Communication
Adapter 3 (RP1210)".