The TU838 MTU can have up to 16 I/O channels. The maximum rated voltage is 50 V and maximum rated current is 3 A per channel. The MTU distributes the ModuleBus to the I/O module and to the next MTU. It also generates the correct address to the I/O module by shifting the outgoing position signals to the next MTU. The MTU can be mounted on a standard DIN rail. It has a mechanical latch that locks the MTU to the DIN rail. The ABB TU838 is an MTU designed for ABB's System 800xA distributed control system.

The TU838 MTU (Module Termination Unit) is designed to facilitate the distribution of ModuleBus to I/O modules and subsequent MTUs in industrial automation systems. It plays a crucial role in generating correct addressing signals for I/O modules by shifting outgoing position signals to the next MTU. Two mechanical keys are used to configure the MTU for different types of I/O modules. This is only a mechanical configuration and it does not affect the functionality of the MTU or the I/O module. Each key has six positions, which gives a total number of 36 different configurations.

It provides connectivity for up to 16 I/O channels between field devices and the control system. The TU838 is an Extended Module Termination Unit featuring 2x4 fused transducer power outlets, 16 signal terminals, 2x4 return terminals, and 2x2 L+ and L- terminals. This module is designed for horizontal mounting. The module utilizes standard communication protocols to ensure efficient data exchange with the 800xA system. It operates on specific voltage and current specifications, which are detailed in the technical documentation.