1.6 Laboratory Safety and Tools
1.6.6 Workplace testing equipment

Computer system repair often requires diagnosing problems by testing electrical signals on a motherboard or its components. In addition, testing the external power environment is often necessary. A troublesome power source can cause difficulties for a computer system that is plugged in. In addition to the outlet tester and digital multimeter, wrap plugs should be part of the standard equipment kept in the workspace. These plugs are also referred to as loopback plugs, or loopback connectors.

Loopback connectors test signaling ports that are located on the back of the computer. The loopback plugs are wired so that they either loop or send the signals back on themselves. These plugs are used in conjunction with suitable test software to check the integrity of computer ports.