Hello friend!
The multiplexer and decoder may both be used to transmit signal but they are different from each other. The multiplexer will transmit raw and unused information. The decoders will interpret the different signals that they receive. There are instances when there is so many information that people will receive that they do not know which one they should focus on first.

This is where the decoder can be very helpful because this will make sure that the right details will be decoded and sent to the receiver clearly. Without a decoder, interpreting signals will be complicated. Companies use the multiplexers in order to send different signals and the decoder will interpret them.