Fiber optic cable 4-core fiber color

The standard color sequence for the four fibers in a 4-core fiber optic cable is Blue, Orange, Green, and Brown.

Internal Fiber Colors

According to the TIA-598-C standard, the first four fibers in a multi-fiber cable are color-coded as follows: BlueOrangeGreenBrown This sequence is used universally for both single-mode and multimode fibers to ensure proper identification during splicing, termination, and troubleshooting. In a loose tube cable, the tube containing these fibers is often Blue or White, while the fibers inside follow the Blue/Orange/Green/Brown order.

Outer Jacket Colors

The outer jacket of a fiber optic cable may differ from the internal fiber colors and is typically used to indicate the fiber type or performance rating rather than the individual fiber positions. Common outer jacket colors include: Yellow for single-mode fiberOrange for multimode OM1/OM2Aqua for multimode OM3/OM4Magenta for OM5 These colors help technicians quickly identify the cable type and its maximum supported bandwidth.

Practical Notes

The color coding is critical for avoiding miswiring and ensuring correct duplex connections. In a 4-core cable, two fibers are often used for a duplex link (Transmit and Receive), while the remaining two may serve as backup or redundancy fibers. Following the TIA-598-C standard ensures global consistency, allowing technicians to work with cables from different manufacturers without confusion.

By adhering to these color standards, fiber optic installations remain organized, safe, and efficient.