In order to reduce solar heating inside automobiles, many vehicular windows incorporate low-E metallic coatings. While this solution has been effective in solar control, it has the unfortunate side effect of RF shielding the interior of the vehicle. As a result, the effectiveness of RF-based systems, such as remote keyless entry, garage door openers, and tire pressure monitoring systems, is reduced.
In addition, bus systems, such as CAN and J1850 type systems, have been used to facilitate intra-vehicular communication. These bus systems are used, for example, to control outside mirror functions, such as mirror position, electrochromic dimming, and turn indicators. It is not desirable to provide access to the vehicle bus in the outside mirror, however, because such access may compromise vehicle security.
There is a need for a bi-directional communication system between the inside of the vehicle and the outside of the vehicle, and especially an outside mirror, which will accommodate a solution to the foregoing problems. Moreover, it has been found desirable to reduce as much as possible the number of wires between the inside of the vehicle and the outside mirrors.