Answer Description

Tone generator/probe will help you identify which cable runs to your office so you can see if it is connected. A loopback plug is for testing the NIC, which we already confirmed good. PING is an application/command used to test network connectivity, it won't help here. A cable tester would likely be the next tool used once we find our cable and confirm that it is connected.

Wikipedia

A signal generator is one of a class of electronic devices that generates electrical signals with set properties of amplitude, frequency, and wave shape. These generated signals are used as a stimulus for electronic measurements, typically used in designing, testing, troubleshooting, and repairing electronic or electroacoustic devices, though it often has artistic uses as well. There are many different types of signal generators with different purposes and applications and at varying levels of expense. These types include function generators, RF and microwave signal generators, pitch generators, arbitrary waveform generators, digital pattern generators, and frequency generators. In general, no device is suitable for all possible applications. A signal generator may be as simple as an oscillator with calibrated frequency and amplitude. More general-purpose signal generators allow control of all the characteristics of a signal. Modern general-purpose signal generators will have a microprocessor control and may also permit control from a personal computer. Signal generators may be free-standing self-contained instruments, or may be incorporated into more complex automatic test systems.