Which article pertains to equipment used for transmitting radio signals?

The correct answer is the article that specifically addresses the requirements for communications and antenna equipment used for transmitting radio signals, covering the installation and safety standards necessary for these types of systems. This article outlines the necessary provisions, including grounding, bonding, and the protection of electrical components from various environmental factors.

Article 810 focuses on the installation of antennas and the associated equipment, ensuring compliance with safety and operational standards primarily for radio signal transmission. This includes considerations for hazardous locations, signal quality, and equipment ratings, thereby providing a comprehensive framework for safe operations in these systems.

The other articles listed pertain to different types of communication systems and equipment but do not focus directly on radio signal transmission. Article 820 covers community antenna television (CATV) systems, while Article 830 addresses the requirements for network-powered broadband communications systems. Article 840 pertains more to information technology equipment and telecommunications, which does not encompass the scope of radio transmission specifically.