A VCO can be configured to convert an analog input signal to a digital output signal. The ionic conductive film includes a material with ionic conductivity ranging from 0. If there are N tracks in a hypertrack then the islands in each track of a hypertrack are shifted in the along-the-track direction by 1N times IS from the islands in adjacent tracks in the same hypertrack. The level of the maintained field-weakening current enables the machine to operate in a safe mode so that the inverter is protected from excess voltage. The calling party is notified that the called party is not in auto-answer mode and that the PTT invitation must be accepted before a PTT call session can occur.