CA2071931A1 - Cell switch - Google Patents

Abstract

Appendix A p.1 Abstract Cellular communication technology has added a new dimension to driving a vehicle. In addition to being able to receive voice and music signals through the car radio, the vehicle driver is able to participate in separate two way telephone communications. The coincidence of these stimuli can create an unacceptable or dangerous situation.
This new device is designed to interface between the car stereo and the cellular telephone. It is designed to interrupt the sound emanating due to the normal operation of the car stereo upon reception or placement of a cellular phone call.

Description

S~ecification ~he device is a an electronic sensor integrated with an electro mechanical switch. It is a single point of interface between two audio sources and one set of speakers. ~he audio sources considered are any car sound system and a cellular phone. The device is compatible with any cellular phone that operates on DC
power generated from the host vehicle.
While this device employs existing electro mechanical devices, it is innovative in respect to its system configuration and its application. Specifically if a car stereo is on at sound levels above normal, upon receiving a cellular phone call it is conceivable that the driver might not hear the incoming audible alert. Even upon hearing the alert the driver would then have to either turn the stereo or radio down, shut off the cassette deck or compact disk player and then answer the phone call. By making use of the unique protocol implicit in the cellular phone operation, the device described herein obviates the need for the above. The function of the device is described below:
Upon reception of an incoming call, the device performs the following:
a) Mutes the existing audio si~nal coming through the car stereo speakers.
b) Broadcasts the incoming phone ringing tone over the same car speakers.
Upon answering of the call:
a) Broadcasts the incoming party's conversation over the stereo speakers.
b) Protects the car stereo amplifier outputs during the conversation.
Upon termination of the call:
a) Returns the car stereo to normal operation.

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r ~ 2~)71931 p.2 If the vehicle driver initiates a phone call the device functions as above except that the sending of the call initiates the process instead of the reception. It must be noted that the cellular telephone audio signal is broadcast over the car stereo speakers regardless of whether the stereo itself is on or not.
In the drawing that illustrates the embodiment of the invention, figure 1 is the generalized block diagram of the system. The existence of slight variations are recognized, and are considered part of this patent application. Black 1 is a power conditioner, required to eliminate spikes and transients generated by the automobile electrical system. Block 2 is the current sensing element; this element outputs a voltage proportional to the current draw of the cellular phone system. Block 3 is the reference voltage and threshold setting block. Block~4 is the decision block where the reference voltage is compared to sensed voltage. Block 5 is the commutating block where the output of the decision block is used to select the source used to drive the speakers. Block 6 is the dummy load block used to absorb the power from the auto stereo during the period when it is disconnected from the speakers.
In the embodiment shown in Figure 1, the concept is applied to a stereo radio system; it is noted that the block diagram and the design can be extended to any number of channels. These situations form part of this claim. The commutating functions of block 6 are accomplished using devices whose primary characteristics are resistive, ideally loss less in order to avoid generating harmonic or non-linear distortion of the commutated audio signals.

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Claims (3)

1) A combination of sensors and electro mechanical devices which will direct the flow of two audio signals to one or more outlets using current draw as a source of the controlling signal.

2) The application of the above to cellular phone and vehicle audio systems irrespective of implementation circuit topology.

3) The application of (1) above to systems comprising one or more speaker sets.