"There are two types of cable for carrying digital information: optical fibre cables and coaxial cables.
The most popular is optical fibre with standard Toslink connections, composed of an optical fibre. Transformed into light pulses, the digital information is carried from the source to the amplifier in this way. The advantage with optical fibres is that there is absolutely no signal loss, even in theory over kilometres, which leads one to believe that this is the ideal conductor. However, due to miniaturisation, some problems can be had with the Toslink connections, which have the unfortunate tendency to not want to line-up with each other, which can lead to transfer errors. It should also be mentioned that the optical fibres can either be made from plastic or glass, the latter being of better quality, but more expensive.
Classic Coaxial cable (or "coax"), with impedance normalised at 50 Ohms, carries digital information in the form of electrical impulses. Due to the fact that the frequency level of a digital signal is quite high, it’s best to choose a good quality cable, while remaining reasonable in price. "