A simplex multiplexer can only perform one of the multiplexing
functions at a time. When a simplex multiplexer is
multiplex recording it displays cameras individually like a
switch. If a simplex multiplexer is being used to
multiplex display the cameras are recorded just like they
are displayed – all in one frame. Simplex multiplexers are
common in unmanned sites, where a multiple camera
screen display is not required.
A duplex multiplexer performs both of these functions at
the same time. A duplex multiplexer has two multiplexing
processors in the same unit. It can display multiple
cameras at the same time while multiplex recording those
cameras. There is usually not a large difference in price
between simplex and duplex multiplexers, consequently
duplex multiplexers are considerably more popular.
