DCI Standards and Codes 4 — Questions and Answers
Question 1: Which pair combination is used for pins 1 and 2 in the T568B wiring standard?
- Blue pair
- Orange pair (Correct answer)
- Green pair
- Brown pair
Correct answer: Orange pair
In T568B, pins 1 and 2 use the orange/white-orange pair, which differs from T568A where pins 1 and 2 use the green/white-green pair.
Question 2: When must a fiber optic installation conform to ANSI/TIA-568.3-D rather than 568.2-D?
- When using multimode fiber only
- When the fiber carries voice signals
- When installing optical fiber cabling components (Correct answer)
- When exceeding 100 meters
Correct answer: When installing optical fiber cabling components
ANSI/TIA-568.3-D is the specific standard for optical fiber cabling components and applies whenever fiber optic cable is being installed.
Question 3: A cable installer is working in a high-rise building and must run cable vertically between floors. Which NEC cable rating is appropriate for this application?
- CMX
- CM
- CMR (Correct answer)
- CMP
Correct answer: CMR
CMR (Communications Multipurpose Riser) rated cable is required for vertical runs between floors because it prevents fire from traveling up through the building via the cable jacket.
Question 4: According to ANSI/TIA-568, the maximum distance from a horizontal cross-connect to a telecommunications outlet in a single-tenant building is:
- 70 meters
- 90 meters (Correct answer)
- 100 meters
- 300 meters
Correct answer: 90 meters
The horizontal cabling subsystem allows a maximum of 90 meters for the permanent link, from the HC (Horizontal Cross-connect) to the TO (Telecommunications Outlet).
Question 5: What is the primary purpose of the ANSI/TIA-758-B standard?
- Indoor horizontal cabling
- Customer-owned outside plant cabling (Correct answer)
- Data center infrastructure
- Residential cabling
Correct answer: Customer-owned outside plant cabling
ANSI/TIA-758-B covers customer-owned outside plant (OSP) telecommunications infrastructure, including cabling between buildings on a campus.
Question 6: Under IEEE 802.3bt (PoE++), what is the maximum power that can be delivered over a single 4-pair cable?
- 15.4 watts
- 30 watts
- 60 watts
- 90 watts (Correct answer)
Correct answer: 90 watts
IEEE 802.3bt Type 4 (PoE++) specifies up to 90 watts of power delivery over a 4-pair cable, requiring Category 6A or better cabling.
Question 7: Which fire code organization publishes the Life Safety Code (NFPA 101) that affects telecommunications installations in buildings?
- UL (Underwriters Laboratories)
- NFPA (National Fire Protection Association) (Correct answer)
- ICC (International Code Council)
- OSHA
Correct answer: NFPA (National Fire Protection Association)
NFPA publishes NFPA 101 (Life Safety Code), which governs means of egress and fire safety requirements that impact how cabling can be routed through buildings.
DCI Standards and Codes 4
Which pair combination is used for pins 1 and 2 in the T568B wiring standard?