  We have analyzed Rossi X-ray Timing Explorer spectral data of the Galactic
micro-quasar GRS 1915+105 in its various spectral states, as defined by Belloni
et al. (2000). In states A and B the spectra are dominated by a strong soft
thermal component, accompanied by a weak harder tail. The soft component is
rather complex and cannot be described as a simple accretion disk emission.
Relativistic effects in Kerr metric contribute to the complexity of the soft
component but are not sufficient to fully account for it. As found previously,
state C spectra are dominated by a Comptonized component, with small
contribution from disk photons. The X-ray reprocessed component is highly
significant in those spectra and, in contrast to the usual hard state spectra
from accreting black holes, it is highly ionized.
