Fiber optic, copper, analog, and digital. These all describe different types of cables. Most cables are copper and now digital. That means that they use copper wire to conduct electrical signals over a digital connection using 1’s and 0’s by pulsing off and on at ultra fast speeds. Analog cable on the other hand uses modulating frequencies, voltage, or current to represent changes in signal. Lastly, fiber optic cable actually uses pulses of light to represent the digital 1’s and 0’s and can travel much farther and with less interference since they are not affected by electromagnetic interference because it is relying on pulses of light and not changes in voltage to carry the signal.
XLR cables use copper wire to send balanced signals over an analog connection. This uses 3 pins connected to 2 wires and a shield. Pin 1 is the ground connection, the cable shield. Pin 2 is the positive polarity connection or “hot”. Pin 3 is the negative polarity connection or the “cold” connection. The same signal is carried over pins 2 and 3 except one is flipped in polarity. This means that at the receiving end, usually a mixer, it can take the 2 signals and compare them, any voltage differences between the 2 signals when it is flipped back is rejected as electromagnetic interference noise that was added along the run of the cable.
Most other cables in AV that carry signals are digital over a copper connection. HDMI, displayport, and DVI are digital video standards. DMX and artnet are digital lighting standards. AES50, dante, AVB, and WSG are all digital audio standards. Thunderbolt and USB are digital standards that are for computer peripherals.