Long-range 10G optical modules enable high-speed data over distances up to 80km. Learn about types, specs, compatibility, and choosing the right module. This article explores the differences between long-range and short-range 10G modules, when to use each type, and how FS products can help you build the right network infrastructure. What Are Short-Range and Long-Range SFP Modules? In optical communication, SR and LR SFP modules are among the most. An SFP (Small Form-factor Pluggable) module transmits data over fiber using specific wavelengths and power levels, which directly influence how far the signal can travel before degradation occurs. This is why two modules with the same form factor can have dramatically different ranges—some limited. PAM4 (4-Level Pulse Amplitude Modulation): This is the predominant modulation technique used in 400G modules. PAM4 allows each symbol to represent two bits of information, effectively doubling the data rate compared to traditional NRZ (Non-Return-to-Zero) modulation 1. The maximum range of a fiber optic cable is not a property of the cable alone — it is the result of a balance between link attenuation and the sensitivity of the active equipment. Long-distance variants, typically referred to as LX, EX, ZX, or ER/LR SFPs, are engineered with higher optical power budgets and longer wavelength.