NGC 5548 was observed by BeppoSAX in a single long (8 day) observation from 0.2 to 200 keV. We find (1) the spectral variation of the source is produced by a change of the intrinsic power law slope; (2) a high energy cut-off at $E_c= 115^{+39}_{-27}$ keV with a hint of change of $E_c$ with flux; (3) OVII and OVIII absorption K edges, and a possible blended OVII-OVIII K$alpha,beta$ emission feature at $0.54^{+0.07}_{-0.06}$ keV, inconsistent with a purely photoionized gas in equilibrium. We propose that the temperature of the absorbing and emitting gas is $sim 10^6$ K so that both collisional ionization and photoionization contribute.
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