What Is Mechanical Barriers In Communication?

The barrier caused due to a minor or major problems caused due to a machine or specifically a equipment that is not whole and solely human dependent!!!!
E.g. A speaker giving speech in open on a microphone and speakers, if suddenly the power is cut off and the speaker is no more able to give speech.
This type of barrier is called as mechanical barriers....

State and explain any three significantly differnt mechanical means of communications available to modern organizations today