twinaxial

Twinaxial, or twinax, refers to a type of cable designed to carry two coaxial signal paths within a single outer jacket. In a typical twinaxial construction, two independent coaxial conductors share a common outer shield or are enclosed together inside one sheath. Each path consists of a central conductor, dielectric insulation, and its own shielding, providing good isolation between the two signals while maintaining a compact form.

Electrical characteristics of twinaxial cables include relatively controlled impedance, commonly around 100 ohms, and good shielding to minimize crosstalk and external interference. This configuration supports relatively high-frequency operation and high data densities compared with separate round cables in the same form factor. The precise performance depends on the conductor layout, dielectric materials, shielding arrangement, and the quality of terminations and connectors.

Applications and history: twinaxial cables have been used in high-speed data and I/O interfaces, notably in certain IBM mainframe and minicomputer environments and in specialized data communications setups during the 1980s and 1990s. They offered a compact, shielded solution for dual-channel or differential signaling needs where space and performance were critical. Over time, many installations migrated to fiber or other copper technologies, but twinaxial cabling remains in use in legacy systems and niche applications requiring dense, shielded dual coax paths.

Connectors and maintenance: proper impedance-matched connectors and terminations are essential to preserve signal integrity. Installation emphasizes consistent shielding continuity and careful routing to minimize interference and reflections.