Color sorting of four-core optical cables

The standard color sequence for a 4-core optical fiber cable is Blue, Orange, Green, and Brown according to TIA-598-C.

Standard Color Sequence

For a 4-core optical cable, each fiber is individually color-coded to simplify identification during splicing or termination. Following the TIA-598-C standard, the first four fibers are always: BlueOrangeGreenBrown This sequence applies to both single-mode and multimode cables, though the outer jacket color may differ: yellow for indoor single-mode, black for outdoor single-mode, and orange, aqua, or violet for multimode cables depending on the type (OM1–OM4) and installation environment.

Practical Tips for Sorting

Loose Tube Construction: In cables with a loose tube, the tube itself is often blue or white, and the fibers inside follow the Blue/Orange/Green/Brown order. Duplex Links: A 4-core cable typically supports two duplex links (two fibers per link) or one duplex link plus two backup fibers. Sorting the fibers in the standard order ensures proper pairing for transmit and receive channels.

Splicing and Termination: Always maintain the color sequence when terminating fibers into patch panels or connectors to prevent miswiring. Use a fiber identifier or visual inspection to confirm the order before splicing. Labeling: For outdoor or armored cables with black jackets, check the printed legend on the jacket to confirm fiber type and sequence, as the jacket color alone may not indicate the fiber order.

Summary

To sort a 4-core optical cable correctly: Identify the outer jacket type (single-mode or multimode). Open the cable and locate the fibers inside the buffer tube. Arrange the fibers in the Blue, Orange, Green, Brown order.

Pair fibers according to your network design (duplex or redundancy). Confirm with labeling or testing before final splicing or termination. Following this method ensures consistent, error-free installation and aligns with international standards for fiber optic cabling.