Spectral states of 1E 1740.7-2942.

1E1740.7-2942, the hardest bright source close to the dynamic center of our Galaxy has been systematically studied by GRANAT in 1990-1992. The 40-150 keV flux varies from the 130 mCrab level to less than 10 mCrab on time scales of months to years. In addition to a state in which the luminosity and the spectral shape resembles that of Cyg X-1, a 'low' state and two different hard states with excess at high energies were observed. These hard states are likely to be connected with the e(+)e(-) annihilation process.