2026-09-19
Optical fiber and coaxial cable differ in speed, immunity, and price. In home and civilian markets, coaxial cable retains higher penetration thanks to its price advantage, but it only covers short-range video transmission; signals over several kilometers require fiber.
Three coax impedances are common in LANs: 75Ω (RG59, the CATV standard, up to 300-400 MHz), 50Ω (thick RG-8/RG-11 and thin RG-58), and 93Ω (RG-62 for Arcnet).
Optical cable consists of a core (germanium/phosphorus-doped silica), cladding, and a high-strength protective layer. Fiber comes in single-mode (core/cladding about 8.3/125 μm, high capacity, relatively expensive) and multimode (commonly 62.5/125 μm). Fiber transmits in one direction only; bidirectional links need fiber pairs.
Selection advice: coax remains cost-effective for short-range, cost-sensitive CCTV; fiber is the better choice for long-haul, high-capacity backbone links. The two are complementary in practice.