What needs led to the implementation of ASCII codes?
Those r "number" systems they represent just numerical values. ASCII is a standard "coding" that include characters 

(encode them as digital binary number, for example "A" is represented as 65)

Think of it as a fn that maps each number/character/symbol(enter for ex. has a code that I don't remember now)  to a code number that will be represented to the computer in binary format