What is the maximum backbone distance for 100-ohm UTP for voice applications?

What is the maximum backbone distance for 100-ohm UTP for voice applications?

• A. 90 meters
• B. 2000 meters
• C. 800 meters
• D. 60,000 meters

Answer: (C)

The main idea being tested is how far a 100-ohm UTP backbone can run between backbone distribution points in a voice system. The backbone is the portion of the cabling that links major wiring closets or telecommunications rooms, and its length is limited by how much the signal attenuates and how well the impedance and electromagnetic integrity are preserved over distance. For voice applications using 100-ohm UTP, the standard allowance is up to 800 meters between distribution points. This distance balances keeping signal levels and quality within acceptable margins while still allowing practical building layouts. Distances like 90 meters are typical for horizontal runs (from a work area to a telecom closet), not the backbone between large nodes. Very long figures such as 2000 meters or 60,000 meters exceed what copper UTP can reliably carry without extreme repeaters or would be impractical in building environments, making them unsuitable. Hence, 800 meters is the best fit as the maximum backbone distance for this scenario.

The main idea being tested is how far a 100-ohm UTP backbone can run between backbone distribution points in a voice system. The backbone is the portion of the cabling that links major wiring closets or telecommunications rooms, and its length is limited by how much the signal attenuates and how well the impedance and electromagnetic integrity are preserved over distance. For voice applications using 100-ohm UTP, the standard allowance is up to 800 meters between distribution points. This distance balances keeping signal levels and quality within acceptable margins while still allowing practical building layouts.

Distances like 90 meters are typical for horizontal runs (from a work area to a telecom closet), not the backbone between large nodes. Very long figures such as 2000 meters or 60,000 meters exceed what copper UTP can reliably carry without extreme repeaters or would be impractical in building environments, making them unsuitable. Hence, 800 meters is the best fit as the maximum backbone distance for this scenario.