Networks use digital transmission

Networks use digital transmission:
(as opposed to (older) analogue systems)
•all information represented by bits(only values are 0 and 1)
•more resistant to noise,which unpredictably changes transmitted values
•basic idea: transmit two very differentsignals for 0 and 1
•even if these signals are corrupted during transmission, they should still be distinguishable–and as long as the destination can distinguish 0 and 1, who cares about noise ?!
•in addition, extra bits (not part of the information to be transmitted) can be added in order to reduce noise effects
•e.g. automatically correct bit errors
•may require analogue-to-digital &/or digital-to-analogue conversions (e.g. if input/output information is in analogue form)