CompTIA Network+ Practice Test

Which signal type is used in multimode fiber cabling?

1. Infrared light only

2. Red laser light only

3. Inexpensive LED light sources

4. Microwave signals

The correct answer is: Inexpensive LED light sources

Multimode fiber cabling primarily utilizes inexpensive LED light sources for signal transmission. This is because multimode fibers have a larger core diameter compared to single-mode fibers, allowing multiple modes or paths of light to propagate through the cable simultaneously. The LED light sources are cost-effective, making them a popular choice for short-distance communication where the decreased bandwidth and distance limitations of multimode fiber are not a concern. Using LEDs is particularly advantageous because they can transmit light over shorter distances efficiently while providing sufficient bandwidth for many applications within data centers, local area networks (LANs), and other environments where high bandwidth is needed without the expense of using lasers. In contrast, while infrared light is commonly associated with certain types of fiber optics, it is not exclusively confined to multimode applications, nor is red laser light specifically tied to multimode fibers; red lasers are more often associated with single-mode fibers. Microwave signals also do not apply to fiber optics, as they pertain to different types of wireless communication technologies. The correlation of multimode fiber with LED sources is paramount in understanding its application and effectiveness in network communications.