
5 Serial versus parallel
When digital data is transmitted from one device to an-
other, there are two ways it can be done. The bits may
all be sent at once, each bit having its own line, this be-
ing known as parallel transmission. Alternatively, the bits
may be sent one at a time, that is one after another in
what may be called a bit stream. This is known, logically,
as serial transmission. Obviously with this latter method
only a single line (plus a return) is needed.
There are two arguments in favour of sending data seri-
ally. The most obvious one is that only the two
conductors, one forward and one return, are required,
no matter how man