BELLCORE's national standard fiber core sequence is: Blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, cyan; The color scale must comply with the Munsell color scale, which is also the most comprehensively implemented color scale arrangement in the. BELLCORE's national standard fiber core sequence is: Blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, cyan; The color scale must comply with the Munsell color scale, which is also the most comprehensively implemented color scale arrangement in the. Science following a process that includes an open comment period. This Proposed Standard will be submitt Proposed Standard to other publications under development by OSAC. Scope: This Standard specifies performance, transmission, and test and measurement requirements for premises optical fiber cable. 5. 1 This guide is designed to assist an examiner in the selection of appropriate sample preparation methods for the analysis, comparison, and identification of fibers using IR spectroscopy. IR spectroscopy can provide additional compositional information than is obtained using polarized light. At present, the color of the optical fiber and fiber casing within the fiber optic cable is generally identified by full chromatography, and the use of natural color is allowed without affecting the identification. An Optical Time Domain Reflectometer (OTDR) is require Domain Reflectometer (OTDR).