Digital and Analogue Signals.... When learning about digital and analogue signals, I have been told that a fibre optic cable can be used for digital signals, whilst a copper wire is usual used in the case of anaolgue elctrical signals. My question is could they be used for the other things? Ie - can you use a copper wire for a digital signal and a fibre optic cable for an analogue signal? And if not why? Its just people never suggest using a copper wire for a digital signal and vice versa. Thanks.