What needs led to the implementation of ASCII codes? Prior to ASCII existing, we already had at least four number systems, namely 

Binary 
Decimal 
Octal
Hexadecimal


So what were the needs that lead to the implementation of ASCII codes? Why was this code chosen, from a computer architecture perspective? 
I have searched online, but I haven't found a satisfactory answer.
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