How telegraph codes became a common language for computers
ASCII grew out of a practical problem inherited from telegraphy: machines needed agreed-upon codes for sending letters and instructions over wires. Earlier telegraph systems had their own code conventions, and computer makers likewise used differing ways to represent text. A code that meant one character on one machine could mean something else on another, making information hard to exchange reliably.
The design choice behind ASCII
The American Standard Code for Information Interchange, standardized in 1963, assigned numbers to a shared set of characters. Its seven-bit design could represent 128 values. These included uppercase and lowercase English letters, digits, punctuation, and control characters—codes that signal actions such as starting a line or moving to the next one, rather than displaying a symbol.
That mix reflected ASCII’s communication roots. A text stream was not just visible writing: it also needed instructions that helped devices handle and transmit it. Once computers agreed on the same assignments, the code for “A” could travel between compatible systems without being reinterpreted as a different character.
A standard with limits
ASCII made basic English text easier to move among computers, but its character set was narrow. It did not include most accented letters or writing systems beyond English, so later encoding standards expanded the range of characters computers could represent. ASCII’s influence remained: many later systems preserve its original assignments for basic English letters, numbers, and punctuation.
The lasting change was not merely a way to label letters. It was a shared agreement that let text survive the trip from one machine to another.
