Which type of transmission requires clear line of sight for successful communication?

The correct response indicates that both laser and microwave transmission necessitate a clear line of sight to function effectively.

Laser transmission relies on light waves, which require unobstructed pathways to maintain signal integrity. Any physical obstruction can lead to signal disruption or loss, making line of sight crucial for successful communication. This principle is particularly evident in applications where lasers are commonly used, such as in optical fiber networks or certain secure communication systems.

Microwave transmission also fundamentally depends on line of sight. It typically uses radio waves that travel in straight lines over certain distances. Similar to lasers, if there are obstacles in the transmission path, such as buildings or terrain, the signal can be diminished or entirely blocked. This is why microwave alignment is often critical in communication satellite systems and terrestrial microwave relay stations.

By understanding these characteristics, it becomes clear why both transmission types share this requirement. Ultrasonic transmission, however, operates via sound waves, which can bend around obstacles and do not strictly require a clear line of sight, making it fundamentally different from the other two methods. Thus, the combination of laser and microwave transmission requiring clear line of sight is a defining feature of their operation.