Rockwell International Corporation

Lucent Technologies Inc.

At+t Corp.

Wescom, Inc.

Ian A Schorr

Ronald Joseph Rees

Dewayne Alan Spires

Akhteruzzaman

Akhtar Akhteruzzaman

Gregory P Pucci

Bruce R Miller

John P Dorth

Mark J Beegle

A method and system for responding to security system inoperability due to damage of a telecommunications line interconnecting the security system to its central monitoring service system requires origination of a wireless telephone call. A wireless unit is interconnected to the security system and originates an emergency call upon detection of telecommunications line abnormalities. Upon establishing a call connection between the wireless unit and the central monitoring service system, the wireless unit relays dual tone multifrequency (DTMF) signals which identify the security system affected by the breach so that appropriate authorities may be dispatched. In alternative embodiments, the wireless unit is programmed to place calls to other designated telephone numbers.

Method and system for responding to security system breaches via a wireless network

A method and system for providing redundancy for security systems served by the public switched telephone network (PSTN) includes a cable modem interconnected to a security system controller. Upon detection of inoperability of a telecommunications line serving the system via the PSTN, the cable modem extends an alert message to a security monitoring service via a packet data network. Advantageously, the cable modem can also send video images and audio from the secured premises to the security monitoring system due to the bandwidth capabilities of the packet data network.

Method and system for providing redundancy in security systems served by

Resistive circuits are provided at the tip and ring of the battery feed circuit as a method of alleviating the need for bulky DC transformers or complex integrated circuitry. The voltage is monitored through a set of comparators eliminating the expense of maintaining fused resistors. The voltages for voice or data transmission is amplified prior to being transmitted. Received signals are AC coupled, with proper biasing, onto the tip and ring lines. Any AC noise on the tip and ring line is shifted 180 degrees out of phase and re-inserted on the line to cancel the noise. As an enhancement to the battery feed circuit, another voltage comparator is added to check the line for DC current signifying an off hook condition.

Battery feed circuit

A circuit and method minimizes undesired noise signals associated with the battery utilized in a telephone battery feed circuit. In one embodiment, the noise voltage is amplified and inverted in phase and added back to a location on the ring line in order to provide substantial cancellation of the original noise voltage which would have appeared at the same location. In another embodiment, the noise voltage coupled to the ring line is reproduced as a replica signal. The replica signal is added in series with the tip line so as to provide equal phase and magnitude relationships relative to earth ground, thereby effectively canceling the noise current which would have flowed from the original noise source.

Telephone battery feed circuit including noise reduction circuit

A semi-floating AC/DC active termination circuit with current sink. A voice frequency transmission line termination circuit has at least tip and ring terminals and provides an AC termination impedance and a DC termination resistance. The circuit has at least a first resistance element connected between the tip and ring terminate which forms the DC termination resistance. A first resistor/capacitor series circuit, having at least a resistor and capacitor connected in series, is connected between the tip terminals and a first virtual ground terminal, and a second resistor/capacitor series circuit, having at least a resistor and capacitor connected in series, is connected between the ring terminal and a second virtual ground terminal. The first resistance element and the first and second resistor/capacitor series circuits form the AC termination impedance. A first operational amplifier has an output connected to the first virtual ground terminal and a second operational amplifier has an output connected to the second virtual ground terminal. The first and second operational amplifiers provide a virtual ground for voltages and currents appearing at the tip and ring terminals. In a preferred embodiment the first operational amplifier has a negative input operationally connected to a voltage source and has a positive input connected to a signal receiving line. The second operational amplifier has a negative input operationally connected to the signal receiving line and has a positive input connected to a circuit ground.

Semi-floating AC/DC active termination circuit with current sink

A fail safe voice system and method for digital telephone networks. The system provides for operation of voice telephone equipment at a customer location when a fault occurs at the customer location. The system has a central office with an analog line termination/digital transceiver connected to subscriber loop lines. The customer location has a digital transceiver/analog station set interface connected to the subscriber loop lines and to the voice telephone equipment. In response to a fault at the customer location the voice telephone equipment is connected directly to the subscriber loop lines thereby eliminating the digital transceiver/analog station set interface.

Fail safe voice system for integrated services for digital network

This disclosure depicts an active network for providing a virtual impedance to a voice frequency loaded pair having tip and ring terminals. The network comprises means for providing a predetermined capacitance between the tip terminal and ground and between the ring terminal and ground and has a variable resistive means. The means has a first input operatively connected to the tip terminal and a second input operatively connected to the ring terminal and also has first and second outputs. First and second fixed resistive means are operatively connected between the first output and the tip terminal and the second output and the ring terminal, respectively. The value of the predetermined capacitance is determined by the first and second fixed resistive means and the variable resistive means in the means for providing a predetermined capacitance.

Active network termination circuit

This disclosure depicts a build out capacitor for use with a voice frequency loaded pair having tip and ring terminals. The circuit comprises means for providing a virtual impedance between the tip terminal and ground and between the ring terminal and ground. The means has a first input connected to the tip terminal and a second input connected to the ring terminal. The means for providing also has first and second outputs. A first fixed capacitor is connected between the first output and the tip terminal and a second fixed capacitor connected between the second output and the ring terminal. The first capacitor is equal in value to the second capacitor.

Build out capacitor circuit

The invention discloses an improved capacitor multiplier which can be applied in both floating coupling and in grounded decoupling applications.

Coupling/decoupling capacitor multiplier

An equalization network is disclosed combining negative slope equalization with low pass filtering and low frequency compensation. The network is for use on electrical lines transmitting electrical signals in the voice frequency range and includes circuitry for inputting and equalizing the electrical signal on an incoming line. A circuit for reverse equalizing the electrical signal, first and second circuits for equalizing the signal, circuits for low pass filtering the signal followed by a supplemental equalization circuit and then a circuit for outputting the signal to the outgoing electrical line are provided.

Reverse equalization network

A prescription attenuator comprising a plurality of cascaded L-pad sections coupled together to form an attenuator network wherein each cascaded section includes a single pole switch for activating its respective section. The network impedance values are selected so that single L-pad section activations produce actual attenuations slightly more than an ideal level of attenuation wherein multiple section activations tend to keep the error evenly distributed about the ideal level of attenuation.

Prescription attenuator having cascaded L-pad sections

A switching regulator generates controllable pulses from a primary d-c. voltage source and then smooths the pulses to form a d-c. output that varies according to the changes in the pulses. A reference voltage source establishes a d-c. reference signal that varies in magnitude with any variations in the magnitude of the d-c. output but with a substantially constant differential in magnitude between the reference signal and the d-c. output. A voltage or current sensor generates a signal that varies in accordance with changes in the voltage or current level of the d-c. output, and a comparator detects the difference between the reference signal and the signal from the sensing means to produce a control signal that varies according to changes in the difference between the two signals. The pulses that form the d-c. output are adjusted in response to the control signal to maintain the output at a regulated voltage or current level. An auxiliary internal power supply is provided for the reference voltage source and the comparator and the current flow is returned through the reference voltage source and the comparator to the auxiliary internal power supply to minimize power losses in the reference voltage source and the comparator. A predetermined d-c. dry voltage is superimposed on the d-c. voltage from the primary source and floats with respect to the reference signal and the d-c. output.

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Chicago, IL, United States of America

Ian A Schorr