220-1101 Question 222
Single answerPunchdown blockA technician is extending telephone service to several office cubicles from a building's telecom closet. The cable runs terminate on a 66 punchdown block, and the technician needs to connect each incoming twisted pair securely and neatly. Which tool should the technician use to complete this task correctly?
- A
Punchdown tool
- B
Crimping tool
- C
Tone generator and probe
- D
Loopback plug
Show answer and explanation
Correct answer: A
Explanation
Punchdown blocks, including 66 blocks commonly used for voice cabling and 110 blocks commonly used in structured cabling, use insulation displacement connectors that require a punchdown tool to insert and secure each conductor. This is standard cabling practice reflected in CompTIA A+ Core 1 objectives covering networking tools and connectors. A crimper is for modular plugs, a toner is for cable identification, and a loopback plug is for interface testing. Best practice is to maintain pair twists as closely as practical to the termination point and use the correct blade type for the specific block.
- A. Correct.
Correct. A punchdown tool is specifically designed to seat and trim wires into insulation displacement connectors (IDCs) on punchdown blocks such as 66 and 110 blocks. In structured cabling and telephone distribution work, this is the proper tool for terminating individual conductors onto the block.
- B. Incorrect.
Incorrect. A crimping tool is used to attach connectors such as RJ-11 or RJ-45 modular plugs onto cable ends. It does not properly seat individual conductors into the IDC terminals of a punchdown block. This is a common confusion because both tools are used in cabling work, but they serve different purposes.
- C. Incorrect.
Incorrect. A tone generator and probe are used to identify and trace cables, not to terminate them. A technician might use this tool to locate the correct pair before working on the block, but it would not be used to connect the wires to the 66 block.
- D. Incorrect.
Incorrect. A loopback plug is a diagnostic device used to test ports or network interfaces by sending transmitted signals back to the device. It has no role in terminating telephone pairs onto a punchdown block.