Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.
If the physical links are shared by more than two nodes/users, it is said to be Multiple Access.
Categories of Multiplexing
a. Frequency Division Multiplexing (FDM)
b. Time Division Multiplexing (TDM)
c. Wave Division Multiplexing (WDM)
Categories of Multiple Access Methods
a.Frequency Division Multiple Access (FDMA) - flexible and simple
b.Time Division Multiple Access (TDMA) - popular
c.Code Division Multiple Access (CDMA Spread Spectrum) - highly secure