Explain ASCII, Unicode and Gray Code

ASCII : ASCII codes represent text in computers, communications equipment, and other devices that work with text. ASCII, pronounced “ask-ee” is the acronym for American Standard Code for Information Interchange. It’s a set of characters which, unlike the characters in word processing documents, allow no special formatting like different fonts, bold, underlined or italic text. ASCII is computer code for the interchange of information between terminals.

An “ASCII file” is a data or text file that contains only characters coded from the standard ASCII character set. Characters 0 through 127 comprise the Standard ASCII Set and characters 128 to 255 are considered to be in the Extended ASCII Set. These codes, however, may not be the same in all computers and files containing these characters may not display or convert properly by another ASCII program. ASCII characters are the ones used to send and receive email.

The reflected binary code, also known as Gray Code after Frank Gray, is a binary numeral system where two successive values differ in only one digit.The reflected binary code was originally designed to prevent spurious output from electro mechanical switches. Today, Gray codes are widely used to facilitate error correction in digital communications such as digital terrestrial television and some cable TV systems. This is a variable weighted code and is cyclic.

This means that it is arranged so that every transition from one value to the next value involves only one bit change. The gray code is sometimes referred to as reflected binary, because the first eight values compare with those of the last 8 values, but in reverse order. The gray code is often used in mechanical applications such as shaft encoders. 

Unicode is an industry standard allowing computers to represent & manipulate text expressed in any of the world’s writing systems. It consists of about 10000 characters, a set of code charts for visual reference, an encoding methodology and a set of character encodings, rules, etc. It allows for combining characters as it contains precomposed versions of most letter combinations in normal use. This makes conversion to and from encodings simpler. It covers almost all scripts like Arabic, Bengali, Greek, Hebrew, Latin, Gujrati, etc. It is used in operating systems, email, web, fonts, etc.