Mechanical communication barriers are issues that arise from problems with machinery or devices used during the transmission of a message. These barriers can include transmission interruptions, power failures, or defects in devices that cause noise interference. An example given is a restaurant server using a pager to transmit a customer's order to the kitchen, but a transmission error occurs and the order does not reach the kitchen on time. To overcome mechanical barriers, alternative transmission methods may need to be used, and senders should ensure devices are properly maintained to avoid disturbances during communication.