Allen-Bradley 1771-DCM Direct Communication Module

The Allen-Bradley 1771-DCM Direct Communication Module (Rev. C01; P: 96221472 A01) is a PLC-5 compatible interface card designed to establish direct data exchange between a supervisory computer and the PLC-5 local processor over the Remote I/O (RIO) protocol. Introduced to meet the growing need for PC-to-PLC-5 communication, the 1771-DCM provides a dedicated bridge on the PLC-5 Remote I/O network that enables reading and writing of PLC data files directly from a host system without additional gateway hardware. The module is intended for use with legacy PLC-5 configurations and corresponding I/O backplanes, and it relies on the 1771 family’s architecture to integrate with existing I/O modules and processors. Its Rev. C01 designation and production identifiers help ensure compatibility with specific hardware revisions and help technicians verify correct installation. Typical applications include SCADA integration, engineering workstations, and diagnostic tools that require direct, programmatic access to PLC state, data blocks, and configuration information through a dedicated communication link within the AB Direct Communication ecosystem.