Tyco Safety Products Canada Ltd.

Aurel Cojocaru

Andrei Bucsa

Stephen D W Fosty

Glenn Nishida

Philip Yan Wong Yu

Philip Yan Yu

A dual or progressive access level security system and method is disclosed. The system receives or acquires one or more initial access identifiers of the user via an identity reader. In examples, the identity reader is a biometric scanner such as a fingerprint scanner that reads a fingerprint, or an antenna such as a Near Field Communication (NFC) antenna that reads an initial access identifier from a tag within a user device such as a fob or mobile phone or a Bluetooth identifier from the user's mobile computing device. In response to validation of the initial access identifier, the system presents virtual keys for the user to enter an access code. In embodiments, the virtual keys are included within a touchscreen and within a virtual projected keyboard presented by the security system. The security system grants access to the user in response to validation of the access code.

Dual access level security system and method

An output interface circuit for a security panel. The output interface circuit includes an output switch for activating one or more output devices in response to a control signal from a port controller. The output interface circuit also includes an overload detection circuit for deactivating the one or more output devices in response to determining that a magnitude of a voltage associated with the one or more output devices exceeds an overload threshold voltage. The overload detection circuit comprises a protection switch for rendering the output switch non or less conductive thereby preventing damage to the output switch and possibly deactivating the one or more output devices when the voltage associated with the one or more output devices exceeds the overload threshold voltage.

Security system output interface with overload detection and protection

The embodiments disclose a circuit for detecting and determining a type of ground fault in a security system. An operational amplifier (OA) having positive and negative inputs and an output may receive AC input signals having different frequencies, fand fat a positive input and provide an AC output signal at the output. An OA feedback loop may comprise a ground fault equivalent impedance connected at the OA negative input and a feedback resistor connected between the OA output and the OA negative input. A rectifier may convert the AC output signal to a DC signal and a filter to obtain a steady DC voltage from the rectified DC signal. A steady DC voltage for two different AC input signals may be obtained and converted to a relative voltage with respect to a constant input voltage amplitude. The relative voltages may be compared to detect and determine a type of ground fault condition.

System and method for ground fault detection and fault type evaluation

An interface circuit configurable in input and output modes comprises a current source; an input/output node; a diode to prevent current from flowing from the input/output node to the current source; a first switch to short-circuit the diode when closed; and a second switch to form a ground path from the input/output node when closed. In input mode, the first switch is closed and the state of a connected sensor circuit may be measured. In the output mode, the first switch is open, and the second switch may be closed to activate an output circuit. In the output mode, power dissipation may be monitored, and the diode may protect the current source and measurement node from current flowing through the output circuit. In the input mode, closing the first switch may prevent the diode from introducing measurement errors due to non-linear attenuation of perturbative AC signals.

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Mississauga, Canada

Aurel Cojocaru