In this essay we will discuss about the common character codes used in non-pc groups. The character codes are: 1. EBCDIC 2. ASCII-8.
Essay # 1. EBCDIC:
EBCDIC stands for Extended Binary Coded Decimal Interchange Code, which is pronounced as “ebb-see-dic”. It is used in IBM mainframe and compatible computers. It consists of 8 binary digits or bits, divided into two fields called Zone and Numeric, each having 4 bits, the Zone preceding the Numeric field.
As you know, four bits can be represented by a hex-digit. In addition to these 8 bits, an additional bit is used during storage, preceding the Zone field, called Parity Bit. It follows even parity system, that is, the number of is in all the bits including the parity bit is made even.
For instance, if the number of Is used to represent a character by the 8 bits is odd, then the parity bit becomes 1 to make even number of Is. If the number of 1s in the other 8 bits is even, then the parity bit becomes 0. It is used for error checking during storage and retrieval. The 9 channel magnetic tapes generally use EBCDIC code.
Some of the EBCDIC codes are as given below:
Essay # 2. ASCII-8:
ASCII-8 stands for American Standard Code for Information Interchange and is pronounced as “ask-ee”. It is also an 8 bit code used in non-PC class of computers. It is different from the ASCII code used in the Personal Computers. It also uses 8 bits to represent a character divided into Zone and Numeric Fields of 4 bits each.
Some of its character codes are given below.
PC – ASCII:
The ASCII code developed for the Personal Computer is a 7 bit code for representing 128 different characters, as detailed below. Among these, the first 32 codes are used for various control purposes like, Line Feed, Form Feed, Return Key press, Bell, etc. which is mainly for printer and communication services, and these codes cannot be printed.
Later on, this 7 bit code has been extended to 8 bits to define up to 256 different characters, the later ones being mostly graphical characters. Incidentally, there are two sets of 8 bit ASCII set, called Extended ASCII characters—one for IBM characters and the other for EPSON characters, the latter includes characters for Italic prints.
The standard ASCII codes are:
