What are the differences between a power cable a signal cable and a data cable?

Answer 1

Power cable is a thick cable connecting your computer to an electrical wall outlet. It can also be a thin wire connecting your modem or other device to a rectangular [ usually ] power supply to your electrical power bar or wall outlet.

Data cables are much thinner, used mainly internally, and can be many wires attached together horizontally to form a wide ribbon of wires. However, a data cable can also be a much thicker cable connecting your modem, router, printer etc. to your computer.

Answer 2

Functional differences

A power cable carries power from some source of power to some device that uses that power.

A data cable carries information ("content") from one device to another device.

Physical differences

Often there is no physical difference between a power cable and a data cable.

The same cable can be used to carry data at one time, and power at some other time.

In fact, several kinds of cables carry data and power at the same time, including telephone landlines, CAT5 Ethernet cables using power-over-Ethernet, the Dallas 1-Wire bus, masthead amplifiers, the cable between the satellite dish LNB and the satellite receiver, etc.

However, often there is a physical difference between a power cable and a data cable: a power cable generally has thicker wire, and generally has only 2 or 3 wires. A data cable generally has thinner wires and often more wires.