Direct connect modem deriving power from telephone line

摘要: A telephone modem which is at least partially powered by electrical power from a line to it connected and further local source, such as extracted digital serial data lines coupled or battery source combination thereof. Telephone used operate all analog signal processing, the remainder of modem, including transmission, reception manipulation, well control functions. In preferred embodiment, optical isolation means provide between differently-powered segments circuitry. The processing segment in manner maintains current requirements constant a.c. impedance, regulated derived intermittent source. specific charge pump circuitry employed extract both positive negative inverted for use power.