Which cable marking designates a 'communications limited use' type of copper cable?

The designation for a 'communications limited use' type of copper cable is represented by the marking typically seen as “CMX.” The "CM" stands for communications multipurpose and is commonly used for general communications cables in residential or commercial installations. However, the "CMX" designation is specifically tailored for cables intended for limited communications use, particularly in indoor and outdoor environments where conditions are less rigorous.

This marking indicates that the cable is suitable for direct burial or running in conduit, as it is more resistant to moisture and outdoor conditions. It is crucial for installers and engineers to understand these designations to select the appropriate cable type based on its intended use and environmental factors, ensuring compliance with relevant codes and safe operation.

The other options, while related to cable types, do not specifically categorize the cable for communications limited use as accurately as CMX does. Understanding these designations is essential for anyone working with cabling systems to ensure adherence to standards and optimal performance.