Dwell-time histograms of the open (A, C, E, and G) and the closed (B, D, F, and H) states obtained from MaxiK channels in the presence and absence of Tl⁺ with the following solutions: 150 mM KNO₃ on both sides (‘K⁺’, black), 50 mM Tl⁺ and 100 mM K⁺ on the luminal side (Tl⁺ lum, green) or on the cytosolic side (Tl⁺ cyt, red). On the opposite side there was always 150 mM KNO₃. 2.5 mM Mg(NO₃)₂ and 2.5 mM Ca(NO₃)₂ were included in all solutions. For the sake of clarity, only representative error bars are given, which were obtained from averaging over the error bars of bins of 25% of the τ value.