What technology allows multiple signals to be sent simultaneously over a single transmission medium?

The technology that allows multiple signals to be sent simultaneously over a single transmission medium is Time Division Multiplexing (TDM). TDM works by dividing the time on a channel into distinct time slots. Each signal is assigned a specific time slot during which it can transmit its data, effectively sharing the same medium without interference. This approach maximizes the use of the available bandwidth, as different signals can be transmitted in succession, giving the illusion of simultaneous transmission.

In contrast, Frequency Division Multiplexing (which is a correct part of the multiplexing technique but focuses on splitting the bandwidth into frequency channels) sends signals on different frequencies rather than in time slots. Amplitude modulation pertains to varying the amplitude of a carrier signal and does not inherently address the issue of multiple signals on a single medium. Signal modulation itself is a broad term that involves adjusting signal properties but is not specific to multiplexing multiple data streams. Thus, Time Division Multiplexing is specifically designed to manage multiple signals within the same transmission medium effectively.