Supplement 47 to ITU-T G-series Recommendations provides information on the general transmission characteristics of single-mode optical fibres and cables specified in the ITU-T G. Graded-Index multimode optical fibres 62,5/125 micron. The fibres are designed for its use at the wavelengths of 850 nm and 1300 nm. The requirements are based on National and International accepted. This article explains eight of the most important global fiber and cable standards — ITU-T, IEC, TIA, ISO/IEC, and Telcordia — covering their scope, applications, and why they matter in real-world deployments. Among these, commonly used standards are G.