Telephonic communications – Subscriber line or transmission line interface
Reexamination Certificate
2005-07-19
2005-07-19
Isen, Forester W. (Department: 2644)
Telephonic communications
Subscriber line or transmission line interface
C379S399020, C379S400000, C379S401000
Reexamination Certificate
active
06920218
ABSTRACT:
Disclosed is a method and apparatus which facilitates the use of existing power that is ordinarily unused or discarded to provide power to a telephone interface circuit when the circuit is in the on-hook state, thereby alleviating the need to use loop current to power the interface during the on-hook state. Existing clock signals are used to charge capacitors that are normally used for capacitive coupling of digital data across the high voltage isolation barrier. Although only small-value capacitors are needed for transmitting data across the capacitive interface, larger-value capacitors are used and are configured to form a charge pump to generate power to the interface at all times. Thus the interface always has a steady source of power available for use, including during the on-hook state for powering circuitry that can detect, modulate, and transmit on-hook signals across the capacitive interface.
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ICs for Communications, Analog Line Interface Solution, ALIS, PSB 4595 Version 2.0, PSB 4596 Version 2.1, Product Overview 08.97 [Note: Unable to Establish if This is Prior Art. Please Examine as Though it is Prior Art].
Analog Modem Front End Meets Many Telecom Standards, New Single Hardware Solution Eliminates The Need for Transformers, Saves Space, and Wears a Small Price Tag, Alfred Vollmer, Communications Technology, Electronic Design, Jul. 21, 1997.
Fuehrer Timothy W.
Hollenbach Keith E.
Laturell Donald R.
Witmer Steven B.
Agere Systems Inc.
Isen Forester W.
Singh Ramnandan
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