TIA-492CAAA:1998 (R2002)

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).