What is transmission?

• A. A rapid change from low to high voltage and back.
• B. The data sent from one device to another.
• C. A standardized method of conveying information from one device to another.
• D. The process of converting digital signals to analog.

Answer: (C)

Transmission is about how information moves between devices using a defined, standardized method. It’s not just the data itself or the act of signaling, but the agreed way that data is conveyed so different devices can understand each other. In a HART-enabled system, the analog 4–20 mA current carries the process variable, while a standardized digital method overlays that loop to transmit device data and diagnostics. So transmission refers to the standardized method of conveying information from one device to another, ensuring interoperable communication. The other options describe the data content, a signaling pulse, or a conversion process, none of which capture the idea of the communication method itself.