Abstract: A light detector includes a semiconductor die that provides a photo sensor. An interference filter is formed on the semiconductor die and has a pass band corresponding to a wavelength of a light emitting diode to supply filtered light in the pass band to the photo sensor.

Abstract: A technique for arbitrating conflicting usage of a communications channel of a wearable communications device is disclosed. In at least one embodiment of the invention, a method includes transmitting a voice signal from a microphone to a portable device using a first communications channel in a first mode of operating a system. The method includes transmitting a monitor signal to the portable device using the first communications channel for a predetermined period of time in response to detection of a beacon signal initiated by an application executing on the portable device. The first and second signals may be ultrasonic signals received over the first communications channel and may have the same frequency and different phases. The beacon signal may be detected based on the first and second signals. The first communications channel may include an audio jack of the portable device.

Abstract: A technique for arbitrating conflicting usage of a communications channel of a wearable communications device is disclosed. In at least one embodiment of the invention, a method includes transmitting a voice signal from a microphone to a portable device using a first communications channel in a first mode of operating a system. The method includes transmitting a monitor signal to the portable device using the first communications channel for a predetermined period of time in response to detection of a beacon signal initiated by an application executing on the portable device. The first and second signals may be ultrasonic signals received over the first communications channel and may have the same frequency and different phases. The beacon signal may be detected based on the first and second signals. The first communications channel may include an audio jack of the portable device.

Abstract: A light detector includes a semiconductor die that provides a photo sensor. An interference filter is formed on the semiconductor die and has a pass band corresponding to a wavelength of a light emitting diode to supply filtered light in the pass band to the photo sensor.

Abstract: A multi-stage surge protector/isolation barrier is provided for connection between a telephony device and a telephone network. The multi-stage surge protector/isolation barrier includes a first stage and a second stage. The first stage is operative to limit or clamp incoming voltage to a pre-defined level. In one form, the voltage limiting or clamping state includes a spark gap and over-voltage/over-current protector. The second stage is operative to limit or dissipate transients developed by the first stage. In one form, the transient limiting or dissipating stage includes transient filter circuitry. The transient filter circuitry may be implemented as LC filter circuitry. The subject multi-stage surge protector/isolation barrier helps prevent damage to the telephony device caused by voltage surges in the telephone network.

Abstract: A multi-stage surge protector/isolation barrier is provided for connection between a telephony device and a telephone network. The multi-stage surge protector/isolation barrier includes a first stage and a second stage. The first stage is operative to limit or clamp incoming voltage to a pre-defined level. In one form, the voltage limiting or clamping state includes a spark gap and over-voltage/over-current protector. The second stage is operative to limit or dissipate transients developed by the first stage. In one form, the transient limiting or dissipating stage includes transient filter circuitry. The transient filter circuitry may be implemented as LC filter circuitry. The subject multi-stage surge protector/isolation barrier helps prevent damage to the telephony device caused by voltage surges in the telephone network.