Coaxial refers to a design in which two conductors or components share a common axis. In audio, video, and signal transmission, it describes a cable with a central conductor surrounded by an insulating layer, shielding, and an outer jacket, all aligned along the same axis to ensure stable, low-loss signal transfer.
The term coaxial is most often associated with coaxial cables, a foundational technology for transmitting high-frequency electrical signals in commercial and industrial environments. In this configuration, the inner conductor carries the signal, while the surrounding shield provides grounding and protection from electromagnetic interference (EMI) and radio frequency interference (RFI). The result is a cable that delivers clean, uninterrupted data, video, or audio signals even in environments with significant electrical noise.
In professional AV and communications systems, coaxial cables are critical for distributing radio frequencies, television signals, and surveillance video feeds. The uniform alignment of the core and shield preserves impedance consistency, which is essential for maintaining signal quality over long distances. Typical impedance ratings for coaxial cables are 50 or 75 ohms, with 75-ohm cables often used in broadcast, CATV, and CCTV applications, and 50-ohm versions commonly used for data and radio frequency transmission.
The term coaxial can also refer to coaxial speakers, where two or more drivers, typically a woofer and tweeter, are mounted along the same central axis to improve sound coherence and frequency response. This design is often used in commercial audio environments requiring compact, full-range sound reproduction.
Commonly defined and tested under Underwriters Laboratories (UL) and National Electrical Code (NEC) guidelines. Performance parameters are also governed by IEEE and TIA standards for signal transmission and shielding integrity.
The coaxial concept was patented in the late 19th century and became commercially viable in the 20th century, coinciding with advancements in radio and television broadcasting. Over time, it became an industry standard for data, audio, and video applications, particularly in structured cabling systems for commercial facilities.