Monitoring equipment for the safety devices used in vehicles when driving in reverse

A monitoring apparatus for a safety device for driving a vehicle in reverse, comprising:

• at least two neighboring transmitter/receiver pairs mounted on a back of a vehicle to measure a distance to an object by reflecting sound off the object, the reflected sound forming an echo, each neighboring transmitter/receiver pair having an associated electro-acoustic transducer;
• means for operating the transmitter/receiver pairs in cyclical alternation to acquire an object by having one transmitter/receiver generate a sound signal and the other transmitter/receiver generate a receiver signal in response to the sound signal;
• an acoustic shunt provided between neighboring transducers for shunting a part of the sound signal to a receiver of a neighboring transmitter/receiver;
• and
• means for evaluating the sound signal received by the receiver of the neighboring transmitter/receiver pair and for generating a malfunction control signal that is indicative of a malfunction.