What type of tool is used to reroute transmit signals in networking diagnostics?

The tool used to reroute transmit signals during network diagnostics is a toner and probe. This device is designed to identify and trace cables, facilitating the re-routing of signals by allowing technicians to monitor and analyze the signal as it travels through a network. These tools work together, where the toner sends a signal down the wire and the probe detects that signal, which aids in diagnosing issues within the network.

In networking environments, it's crucial to have tools that can test and analyze the integrity of connections. The toner can help ensure that the signals are being transmitted correctly and can isolate problems in the network cabling. This capability is fundamental when performing diagnostics or maintenance in complex networking setups.

The other options serve different purposes. Network taps are primarily used for monitoring network traffic without introducing any disturbance to the existing network flow. Loopback plugs are mainly used for testing network interfaces by rerouting outgoing signals back to the incoming port to confirm that the interface is functioning correctly. A punchdown tool is used for connecting and securing wires to a punchdown block or patch panel, not for rerouting signals. Each tool has its designated application in network management, but for rerouting transmit signals specifically, a toner and probe are the appropriate tools.