OPTION SELECT RECOGNITION SCHEME UTILIZING OPTICAL INTERCONNECT
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-16
This invention allows the radio to select an exter- nal option class (external speaker, external micro- phone, external RI?. .) by sensing the amplitude or amount of light allowed to pass through or reflected by the accessory to the radio. This optical option select scheme has various advantages such as: 1) It avoids the problems with sensing an impedance con- trolled voltage to determine an option class, 2) It eliminates I/O pin connections on the universal con- nector for the accessory and the radio, 3) It elimi- nates the associated static protection and filtering needed for those I/OS, 4) It eliminates interference from RF sources that cause desensing in conven- tional accessory option select schemes, 5) It elimi- nates the problem associated with voltage drops caused by extended wire lengths when reading volt- ages to determine option types and, 6) It allows mod- ification of operating characteristics of microphones, such as for use in high/low noise environments, by changing the step density filter at the connector. The signal gains for the microphones would be adjusted in the radio via software.