Which device helps technicians trace cables through walls or ceilings?

The device that helps technicians trace cables through walls or ceilings is a toner/probe. This tool set works by sending a tone along the cable, which can then be detected with a probe. When the toner is connected to one end of the cable, it emits a signal that travels down the cable, allowing the technician to locate the cable by hearing the tone through walls or ceilings with the probe. This is particularly useful for identifying and organizing the large number of cables often found in networking environments.

In contrast, a punchdown tool is primarily used for terminating and connecting wires to a punch-down block or a patch panel, and does not have capabilities to trace cables. Loopback plugs are used for testing network ports by creating a loop for signals but are not meant for tracing cables. A Wi-Fi analyzer is designed to analyze wireless networks, but it does not assist in locating or tracing physical network cables. Therefore, the toner/probe is the most appropriate choice for tracing cables.