Allen-Bradley 1771-ASB RIO Adapter Module | Reliable PLC-5 I/O By wayne No Comments on Allen-Bradley 1771-ASB RIO Adapter Module | Reliable PLC-5 I/O 3 Min Read Explore the Allen-Bradley 1771-ASB Remote I/O Adapter for PLC-5 systems. Supports 57.6-230 kbps, 32 devices, and 2500 ft cable runs.