Thinking about computers primarily, I'm trying to get my head around how data is transmitted along various transmission media. In particular, I'm getting confused between the use of electromagnetic waves (EM) and voltage (V).
Firstly, am I right in thinking that data can be transmitted using either EM waves or V, the former being analogue and the latter being digital?
Secondly, do guided media such as coaxial cables carry EM waves?
Finally, are buses inside a computer electronic? (is this the right word to use here?). I assume that volts are passed along each wire rather than EM waves.
I hope it is ok to ask three questions in one but they are all related. Detailed explanations (without being too technical) would be much appreciated.