Reflectance is measured in decibels (dB) and is always a negative value. A higher absolute value is better! For example, a reflectance of -55 dB is much better than -30 dB because it indicates less light is being reflected. The closer the number is to zero, the higher the reflectance (meaning a poor connection). Optical return loss is given in units of dB and always a negative value for passive optics, with values closer to 0 representing larger reflections. Receiver sensitivity is the lowest optical power level at which an optical receiver can successfully decode data with acceptable bit error rates (BER). It's a core parameter in optical transceiver specifications, indicating the module's capability to detect weak incoming signals. Lower receiver. By MARK MULLINS, Fluke Networks -- The confusion between positive return loss and negative reflectance means that you may see manufacturers specify a negative value for return loss when they really meant reflectance. It is also called. The Telecommunications Industry Association (TIA) standard sets a maximum loss of 0. 75 dB per mated pair, but high-quality connectors often achieve much better performance, typically between 0.