Mobile phone use is pervasive in today's society including use in the home, at work, and in the car. The use of a mobile phone while operating a motor vehicle typically involves holding the mobile phone handset in one hand while using the other hand for steering, shifting gears, adjusting the radio volume, or any of a number of activities. The distraction of handling a mobile phone while driving poses a threat to the safety of the driver and others in the vicinity of the driver and vehicle. Studies have equated driving while using a mobile phone with driving under the influence of alcohol or drugs in terms of the number of accidents caused. Legislation is being considered or has already been enacted in many countries banning the use of hand-held mobile phones while driving. In the United Kingdom, for example, penalties for using such a mobile phone while driving, even if no accident results, can include imprisonment and/or a substantial fine.
Solutions to this problem have appeared in the form of mobile phone hands-free systems. Some automobiles are equipped with a mobile phone hands-free system during manufacture. These systems may integrate a mobile phone with the car audio system, such as the system disclosed in U.S. Pat. No. 5,243,640 of Hadley et al., which is incorporated herein by reference. Hadley's invention describes an interface that effectively shares an output transducer and amplifier between an audio system and a phone in a vehicle. The advantage of this system is clear if it is installed in the car during manufacture. However, drivers of vehicles without this feature who, nonetheless, desire to have the hand-free convenience must have an aftermarket system installed into their vehicles at a cost which may be substantial. Further, an aftermarket installation in a vehicle can often effect the aesthetics of a vehicle interior which was not expressly designed to receive such an installation. Another disadvantage is that the system, as described, is not portable. As a result, a similar system must be installed into every audio system that is used by the mobile phone owner.
An alternate solution for providing hands-free phone operation is in the purchase and use of a mobile phone hands-free kit. These kits are portable and require very little, if any, installation. Such kits, which may have their own audio amplifier and speaker(s), are usually compact, and thus, the audio output of the speakers is typically "tinny". Further, increasing the volume of such speakers to a level sufficient to hear a soft-spoken person at the other end of the connection while in a noisy background can result in distortion of much of the conversation. In contrast, a vehicle's existing audio system, which may be factory-installed or an aftermarket addition, is often sophisticated and of high sound quality, capable of sustaining increased volumes without distortion. Even the most basic audio system that is installed during manufacture of a vehicle avoids the high, thin and metallic sound quality that is present in many currently available hands-free kits.
The interfacing of separate audio components into a vehicle audio system is known. In one example, the use of an automobile audio system for portable Compact Disk (CD) players is disclosed in U.S. Pat. No. 5,319,716 of McGreevy, which is incorporated herein by reference. The wireless radio adapter described therein accepts the stereo signal of a CD player, via an audio-out jack, and transmits a stereo FM (Frequency Modulation) signal to a conventional automobile FM radio. The adapter is configured to accept the right and left stereo inputs of a playback device, and does not have the capability to accept audio from a mobile phone. Further, the McGreevy adapter does not provide a plurality of automatic functions via the use of an internal processor.
In view of the failure of the prior art to provide a solution, the need remains for a means for readily interfacing a mobile phone with an existing audio system, such as in a vehicle, which is economical, portable, and easy to install. Further, it would be desirable to provide a "smart" device that accepts audio from a mobile phone, provides optional receive and transmit functions, and interfaces with an AM or FM receiver of an audio system by means of a low power RF signal transmission.