This term is used to describe a multiplexer that will record pictures to tape and display multiple pictures on a single monitor. A duplex multiplexer will continue to record even when a tape is being replayed. When several images are displayed on a single monitor screen simultaneously, this is called a multi-scene view. Framestore This is an area of memory within a multiplexer that is used to store pictures when they are digitised. Generally speaking, a simplex machine can be considered as having one framestore, a duplex machine has two.
Most multiplexers use asynchronous camera inputs.
This usually makes the system both cheaper and easier to install. All video multiplexers perform time-division multiplexing. This refers to the process of recording all connected cameras by taking a snapshot of each camera in turn. In other words, a slot of time is allocated to each camera. The update rate is the period of time between the first and subsequent recordings of any particular camera.