CINCINNATI MUXI-AB-120 MuxiPort Controller

The MUXI-AB-120 MuxiPort Controller from Tomantron is a 120 VAC-powered RS-232 serial multiplexer designed to interface with CINCINNATI PLCs, providing a compact bridge between a single PLC serial port and two independent user ports. The unit multiplexes the AB PLC’s RS-232 connection into two separate channels, enabling two devices—such as a PC terminal and an HMI or test rig—to share the PLC’s serial link without swapping cables. A built-in status indicator shows power and operation state, helping technicians quickly diagnose communications on the factory floor. This model, labeled MUXI-AB-120, is commonly found in third-party listings as a MuxiPort Controller compatible with CINCINNATI controllers, offered in variations described as new/out-of-box or refurbished. Typical use cases include debugging, data collection, and multi-user access to a single AB serial channel in legacy Rockwell Automation environments, delivering flexible RS-232 access while preserving the integrity of the PLC interface.