As fiber optics are immune to electromagnetic interference, they are better for signal transmission than wire cables.光纤因不会受到电磁波的干扰，所以比一般的金属线更适于传达讯号。Nearly every long-distance call made in Britain now travels on optical fibre instead of cable.现在在英国，几乎所有长途电话都通过光纤而非电缆传输。