RCDD · Question #63
When reviewing a backbone distribution system within a building provided to you for standards compliance, you see that there are several cables with bridge taps built in. Which one of the following op
The correct answer is C. Provide recommendations to remove all bridge taps. Bridge taps are unterminated cable branches that cause impedance mismatches and signal reflections, making them non-compliant with structured cabling standards. All bridge taps must be removed to achieve standards compliance.
Question
When reviewing a backbone distribution system within a building provided to you for standards compliance, you see that there are several cables with bridge taps built in. Which one of the following options is correct?
Options
- AEnsure all cables meet maximum lengths to ensure standards compliance
- BEnsure all cables exceed minimum cable lengths to avoid NEXT(near-end crosstalk)
- CProvide recommendations to remove all bridge taps
- DProvide recommendations to remove one bridge tap per cable
- EDo nothing as the design will pass all design parameters
How the community answered
(59 responses)- A12% (7)
- B8% (5)
- C75% (44)
- D2% (1)
- E3% (2)
Why each option
Bridge taps are unterminated cable branches that cause impedance mismatches and signal reflections, making them non-compliant with structured cabling standards. All bridge taps must be removed to achieve standards compliance.
Ensuring cables meet maximum lengths addresses a separate compliance parameter; it does not resolve the signal integrity problems caused by bridge taps, which are prohibited regardless of the cable length.
Minimum cable lengths relate to avoiding NEXT in very short patch scenarios and are entirely unrelated to bridge taps; bridge taps cause reflections from impedance mismatches, not NEXT, and this action would not achieve compliance.
Bridge taps are stubs of cable that branch off a main conductor but are not terminated at both ends, creating signal reflections and impedance discontinuities that degrade transmission performance. TIA-568 and ISO 11801 structured cabling standards explicitly prohibit bridge taps in compliant backbone installations, so the correct action is to recommend removal of all bridge taps - not a subset - to restore compliance.
Standards require removal of all bridge taps on each cable, not just one per cable; any remaining bridge tap leaves the installation non-compliant with TIA-568 and ISO 11801.
A backbone with bridge taps fails structured cabling standards compliance; doing nothing is incorrect because bridge taps are explicitly prohibited and will cause the installation to fail performance testing.
Concept tested: Bridge tap prohibition in backbone cabling standards
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