Dear all,   how can i logout and login  form cisco ip phone spa502g and spa525g through phone. i didn't saw any logout option. please help urgently

Hi, our company have cisco SPA502G AND SPA525G ip phones. now the problem is some time its get hang and freeze.after that 2 or 3 times to restart to work. some time when dailing it shows service un available.current firmware for SPA502G IS    7.4.9c ...