FASCODE - Fast Atmospheric Signature Code (Spectral Transmittance and Radiance). Using the HIRACC algorithm, a rapid running line-by-line transmittance code has been developed for a layered atmosphere. In addition, the atmospheric radiance is also calculated assuming local thermodynamic equilibrium. The Voigt line shape profile is used for the general case but both the Lorentz and Doppler profiles may be chosen for cases where the Voigt shape is not needed.