1. DEMULTIPLEXER is a data distributor. Also read as DEMUX. It is a process of taking information from one input and transmitting over one of many outputs. It is quite opposite to multiplexer. Demultiplexing is the process of converting a signal containing multiple analog or digital signals back into the original and separate signals.  

2. 1:4 DEMULTIPLEXER consist of one input, four outputs and two control lines to make selections. The input bit is Data D with two select lines S1 and S0. The input bit D is transmitted to four output bits D0,D1,D2 and D3. 

3. TRUTH TABLE OF 1:4 DEMULTIPLEXER