What does the receive cable do in a fiber optics system?

The role of the receive cable in a fiber optics system is primarily associated with relaying signals that have been transmitted through the fiber optic cables. Its main function is to allow the optical signals, which contain data transmitted over the fiber, to be received and then converted back into electronic signals for processing.

In this context, the function that clearly aligns with the purpose of the receive cable is measurement of output power, gaining insights into the level of signals being received. This is crucial for system performance, as it ensures that the signals are strong enough to be processed correctly without significant loss or distortion.

The other options describe functions that do not accurately represent the receive cable's role. Connecting the light source pertains more to the transmit side, while transmitting signals is inherent to the function of fiber cables themselves, not specifically the receive cable. The idea of serving as the main data cable can be misleading, as it does not encapsulate the distinct function of the receive cable within the system architecture. Understanding these distinctions helps clarify the vital role of each component in a fiber optics setup.