SFP distance refers to the maximum effective range over which an SFP optical module can transmit data while maintaining signal integrity. If the optical module works at a wavelength near 850nm (880nm) or 910nm (940nm), then the module is a multi-mode fiber (MMF) optical. In reality, SFP transmission distance is defined by optical design—not data rate. 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. xxx: indicates the rate and rate standard. The module is used for high-speed cable (copper cable) connection. Optical modules can be divided into: 100Mbps optical modules: Usually labeled as 155M, 100Base, FE, etc.