Mitsubishi Electric A1SJ71UC24-R2 RS-232-C Unit Module

The Mitsubishi Electric A1SJ71UC24-R2 RS-232-C Unit Module is a single-channel RS-232-C communication interface for MELSEC-A / A1S Series PLC systems, designed to add serial connectivity within automation control racks. It enables serial communication between PLCs and external devices such as HMIs, computers, and printers, supporting configurable half- or full-duplex transmission at 300–19,200 bps with 7/8 data bits, selectable parity, and 1–2 stop bits, via a 9-pin D-sub (male) connector up to 15 m. This rack-mounted module is used across manufacturing lines, data acquisition, machine control, and PLC-to-device integration wherever legacy RS-232C connectivity is required. Common replacements include AJ71UC24, A1SJ71C24-R2, and QJ71C24N-R2.