CWDM (Coarse Wavelength Division Multiplexing) optical modules follow a dedicated color‑coding system for long‑distance and multi‑wavelength transmission: 1470nm —— Grey 1490nm —— Purple 1510nm —— Blue 1530nm —— Green 1550nm —— Yellow 1570nm —— Orange 1590nm —— Red 1610nm ——. CWDM (Coarse Wavelength Division Multiplexing) optical modules follow a dedicated color‑coding system for long‑distance and multi‑wavelength transmission: 1470nm —— Grey 1490nm —— Purple 1510nm —— Blue 1530nm —— Green 1550nm —— Yellow 1570nm —— Orange 1590nm —— Red 1610nm ——. This article provides a professional guide on transceiver pull tab color codes by wavelength—spanning SFP, SFP+, CWDM, and BiDi modules—and introduces how LINK-PP standardizes color matching across its optical product lines. Every optical transceiver operates at a specific wavelength, typically. In fiber optic networks, accurately identifying the wavelength of an optical transceiver module is essential for ensuring optimal network performance and reliability. One of the most effective and widely used methods is through the pull-tab color on transceiver modules. This simple visual system. In the complex network world of data centers, optical modules play a crucial role, efficiently converting electrical and optical signals to ensure stable, high-speed data transmission across fiber optic networks. Typically, single mode SFP modules are labeled as "SM" or "single mode," while multimode modules may be labeled as "MM" or "multimode.