ALSO SEE TIA-492 SERIES
This Detail Specification applies to a Class IVa dispersion-unshifted single-mode optical fiber. A Class IVa single-mode fiber has a nominal zero-dispersion wavelength in the 1310 nm transmission window. It is commonly referred to as a dispersion-unshifted (or non-shifted) fiber whose dispersion characteristic is approximated by a differentiated Sellmeier equation (see 4.4.4 of the Sectional Specification).
