How can you code analog signals to digital signals in telecom?

use Binariy digits (0 or 1)

we can code analog signals to digital signals through Binary Digits i.e... 0 and 1

Through Pulse code modulation .. that consist od sampling , quantization  translation 

Using A/D which is consisting of three stages

First : Sampling which is must be comply with the Nyquest rate (Higher sampling rate >> Easier & Accurate reconstruction)

Second : Quantization to put each sample at a certain level (More levels >> Higher accuracy)  

Encoding : To translate each quantizied sample into bits (No. of bits = 2 to power of quantization levels)