Abstract: Printer apparatus for use with a dictation system including a changer device having an input stack, a recording deck for recording dictated messages, and an output stack for storing recording media onto which dictated messages have been recorded. The changer device further includes an optical reading element for reading identifying indicia on the recording medium in the recording deck. This information along with other information such as the number of dictated messages recorded on the recording medium, the time of day, etc. are printed out by the printer.

Abstract: A tracking servo circuit corrects for closed loop gain variations due to wear of the disc, the width of the electrode of the reproducing stylus, etc. The disc contains an information track bounded by servo tracks used to derive a tracking error signal. This tracking error signal is supplied to an AGC circuit after being filtered and detected. The gain of the AGC circuit decreases as the voltage level of the tracking error signal increases. The tracking error is also supplied to an electric-mechanical conversion system after an oscillatory signal of constant frequency and amplitude is added to it. The oscillator signal is used to stabilize the gain of the servo loop. The electric-mechanical conversion system corrects the position of the stylus in response to these signals.