A Remote Terminal Unit (RTU) filter is a type of filter that is used to filter out unwanted signals from a system. It is typically used in industrial automation and control systems, and is designed to protect the system from interference and noise. RTU filters are typically used in applications such as HVAC, motor control, and instrumentation. They are also used in communication systems such as Ethernet, CAN, and RS-485. RTU filters are designed to provide a high level of protection from electromagnetic interference (EMI) and radio frequency interference (RFI). They are also used to reduce the amount of noise in a system, which can cause errors in the system’s operation. RTU filters are typically used in conjunction with other types of filters, such as EMI/RFI filters, to provide a comprehensive level of protection.