A CompTIA A+ certified professional’s toolbag most likely includes a set of loopback plugs. What is a loopback plug?
A) A plug that protects ports from dust and dirt
B) A plug that helps test physical port communication
C) A plug that converts between different port types
D) A plug that taps connections for use by test equipment
The answer: B) A plug that helps test physical port communication
There are loopback plugs for many different ports, including serial ports, Ethernet ports, and WAN connections. These loopback plugs are often used in conjunction with testing software to “loop” traffic right back into the port. If the data sent out into the loopback plug is identical to the data received from the loopback plug, you can assume that the basic communication functions of the port are working properly.
The incorrect answers:
A) A plug that protects ports from dust and dirt
Most ports don’t need extra protection from dust unless they’re in a harsh environment. Even then, those protectors aren’t loopback plugs.
C) A plug that converts between different port types
That’s an intentionally vague answer, but you can guess that gender changers might fall into this category. Loopback plugs don’t convert anything, since the purpose of a loopback plug is to test the current port configuration.
D) A plug that taps connections for use by test equipment
Test equipment taps provide additional links into a connection, but a tap isn’t part of a loopback testing function.
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Want to know more? Watch “The CompTIA A+ Toolbag.”Every CompTIA A+ technology professional needs a tool bag with the right mix of diagnostic tools, specialty tools, and cleaning products. In this video, we’ll walk you through the must-have tools that you’ll need for everyday troubleshooting and preventive maintenance. |