Which statement is true about backbone lengths for the three cable types?

• A. Heavy and Mid backbones can reach up to 250 meters, Lite up to 100 meters.
• B. Lite backbones can reach up to 250 meters.
• C. Heavy backbones can reach up to 100 meters.
• D. Mid backbones can reach up to 300 meters.

Answer: (A)

Backbone length is limited by how far the CAN bus signal and power can travel reliably along the main trunk without excessive voltage drop or signal degradation. Different backbone cable types have different electrical capabilities. Heavier and mid-grade backbones use larger conductors with lower resistance, so they can carry power and data farther, up to about 250 meters. Lite backbones use thinner conductors with higher resistance and lower current capacity, which means they’re reliable only over shorter runs, up to about 100 meters. In practice, the exact length can also be reduced by the number of devices on the network and the way drops are arranged, but the baseline limits reflect the inherent differences between the cable types. So the statement that heavy and mid backbones can reach up to 250 meters, while Lite backbones are limited to 100 meters is the correct one.