Temporal evolution of the count rates and spectral parameters of Cyg X-1 during the observation period. The upper three panels are the light curves of Cyg X-1 measured with a) RXTE-ASM (1.5 − 12 keV); b) PCA (total energy range 2 − 60 keV) and c) the Ryle Telescope (at 15 GHz). d) The hardness is the same as in Fig. 12, namely the ratio of the PCA count rates in the energy bands (9.5 − 15 keV)/(4.5 − 5.8 keV). The bottom panels show the temporal evolution of e) the photon index Γ₁; f) the photon index above the spectral break Γ₂; g) the cutoff and h) folding energy of the high-energy cutoff; i) the hydrogen column; j) the inner temperature and k) the inner radius of the accretion disk; and l) the reduced χ² of the best fits. The dashed vertical line indicates the transition.