**1. Definition of multiplexing**

It is fascinating to know that the multiplexing can be employed and defined from different points of views and different disciplines. For example, Dr. E. Julius Dasch, former manager of the NASA National Space Grant Program, defines multiplexing on his dictionary book [1] as:

*…the simultaneous transmission of different data from a spacecraft using a single channel. The data stream is separated into frames that carry codes for different information, such as temperatures, pressures, and the state of on-board computers.*

In a media and communication dictionary book [2], multiplexing is mentioned as:

*Digital television transmission allows for multiplexing, whereby multiple channels are bundled together and sent simultaneously in a single stream of data.*

In a computer science dictionary book [3], multiplexing is described as:

*…the process of combining multiple messages simultaneously on the same physical or logical transmission medium. There are two main types: time division multiplexing (TDM) and frequency division multiplexing (FDM).*

The list continues for the Internet, optic engineering, graphics, phytography, laser and photonics geology, earth sciences, and many more.
