Abstract: A method and apparatus for detecting the connection of an external audio accessory to an audio device via a two-wire audio jack includes providing a DC bias on the output of the audio circuit connected to the audio jack. The audio jack is such that, when a plug is inserted into the audio jack, the DC bias is removed from an internal routing pin of the audio jack. The change in DC voltage at the internal routing pin indicates connection of the external audio accessory. Furthermore, upon detection, the AC response of the external audio accessory can be determined, and used to select a set of audio settings to be applied to the audio components of the audio device to optimize the performance of the external audio accessory.

Abstract: A communication device is configured to receive signals using at least one acoustic microphone and at least one structural microphone. The communication device calculates one of first a signal-to-noise (SNR) ratio and a speech-to-noise ratio for the at least one acoustic microphone from received signals and calculates a SNR for the at least one structural microphone from received signals. The communication device compares one of the first SNR and the speech-to-noise ratio for the at least one acoustic microphone with the SNR for the at least one structural microphone. The communication device selects one of the at least one acoustic microphone and at least one structural microphone to receive speech responsive to the comparing and places a selected one of the at least one acoustic microphone and at least one structural microphone in a standby mode.

Abstract: An intrinsically safe audio circuit and intrinsically safe portable two-way radio device meet conventional audio output requirements and intrinsically safe design limitations by separating the speaker coil of the device's speaker into separate coils to limit the energy storage possible in any one of the coils. Each separate coil is driven by one of several different audio power amplifiers that each output a substantially identical signal, and each of which are current limited.

Abstract: A communication device is configured to receive signals using at least one acoustic microphone and at least one structural microphone. The communication device calculates one of first a signal-to-noise (SNR) ratio and a speech-to-noise ratio for the at least one acoustic microphone from received signals and calculates a SNR for the at least one structural microphone from received signals. The communication device compares one of the first SNR and the speech-to-noise ratio for the at least one acoustic microphone with the SNR for the at least one structural microphone. The communication device selects one of the at least one acoustic microphone and at least one structural microphone to receive speech responsive to the comparing and places a selected one of the at least one acoustic microphone and at least one structural microphone in a standby mode.

Abstract: A method and apparatus for detecting the connection of an external audio accessory to an audio device via a two-wire audio jack includes providing a DC bias on the output of the audio circuit connected to the audio jack. The audio jack is such that, when a plug is inserted into the audio jack, the DC bias is removed from an internal routing pin of the audio jack. The change in DC voltage at the internal routing pin indicates connection of the external audio accessory. Furthermore, upon detection, the AC response of the external audio accessory can be determined, and used to select a set of audio settings to be applied to the audio components of the audio device to optimize the performance of the external audio accessory.

Abstract: An intrinsically safe audio circuit and intrinsically safe portable two-way radio device meet conventional audio output requirements and intrinsically safe design limitations by separating the speaker coil of the device's speaker into separate coils to limit the energy storage possible in any one of the coils. Each separate coil is driven by one of several different audio power amplifiers that each output a substantially identical signal, and each of which are current limited.

Abstract: A portable full duplex communication device (100) is provided with improved acoustic porting (114) by providing an earpiece enclosure (108) within the housing (102) of device. The earpiece enclosure (108) includes an array of micro-ports (114) formed to provide optimal low frequency response and echo performance without the use of external acoustical leak ports to the housing.

Abstract: A method for maintaining transmit audio quality under harsh environmental conditions, the method includes receiving audio signals into a microphone of a portable communication device and determining at least one parameter associated with the received audio signals. In accordance with an embodiment, the at least one parameter is compared with a received audio parameter threshold. When the at least one parameter falls outside of the received audio parameter threshold, the audio routing is switched from the microphone to the loudspeaker. Subsequent communication may revert back to the microphone or remain at the loudspeaker depending on monitored audio conditions.

Abstract: A portable full duplex communication device (100) is provided with improved acoustic porting (114) by providing an earpiece enclosure (108) within the housing (102) of device. The earpiece enclosure (108) includes an array of micro-ports (114) formed to provide optimal low frequency response and echo performance without the use of external acoustical leak ports to the housing.

Abstract: A method for maintaining transmit audio quality under harsh environmental conditions, the method includes receiving audio signals into a microphone of a portable communication device and determining at least one parameter associated with the received audio signals. In accordance with an embodiment, the at least one parameter is compared with a received audio parameter threshold. When the at least one parameter falls outside of the received audio parameter threshold, the audio routing is switched from the microphone to the loudspeaker. Subsequent communication may revert back to the microphone or remain at the loudspeaker depending on monitored audio conditions.