What is the maximum pair/un-twist for Category 3 cable?

• A. 3 inches
• B. 2 inches
• C. 1 inch
• D. 6 inches

Answer: (A)

The main idea is that the length you untwist a pair near the termination affects how well the cable preserves its electrical characteristics. For Category 3 cable, designed for lower-frequency operation, the standard allows a relatively forgiving untwist length, up to three inches. Keeping the untwisted portion to this limit helps limit impedance disruption and crosstalk at the connector, preserving performance for the networks Cat3 supports.

Shorter untwist lengths are fine, but three inches is the maximum specified. Longer untwists would exceed the standard and could degrade performance. For contrast, higher-category cables like Cat5e or Cat6 require much tighter untwist limits (about half an inch) due to their higher-frequency operation.