Hands-free adaptor for phone in vehicle includes interface matching digital voltage levels in telephone and base unit processor

摘要

The hands-free adaptor includes an interface (22) for matching the level of digital signals exchanged between the telephone (10) and the processor (80) of the box. Voltage translators (400,700) modify the voltage levels of signals exchanged between the phone and processor to match the required inputs. The hands-free adaptor includes a universal box and a specific remote support providing a cradle to receive a mobile telephone. The box includes an interface (22) for matching the level of digital signals exchanged between the telephone (10) and the processor (80) of the box. This includes a circuit (500) for measuring the voltage excursion of logic signals produced by the telephone applied to the input of the box, and a voltage translator (400) modifying the voltage level to that required by the processor. A second voltage translator (700) modifies the voltage level of signals produced by the processor in order to match those required by the telephone.