N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 2 - Data Communications Basics and Legacy Technologies                                                 Slide 8 of 45 _________________                                                                                  __________

                         Building Blocks - Codes for Information Exchange

                                        Baudot

                                        Extended Binary-Coded-Decimal Interchange
                                          Code (EBCDIC)

                                        American Standard Code for Information
                                          Interchange (ASC II)

_________________                                                                                  __________

The data transmission codes have evolved over time. Early Morse code , developed for telegraph communications, became obsolete for communications between machines. Over time Baudot, EBCDIC and ASCII codes evolved.

Baudot Code - Developed by a Frenchman named Emile Baudot in 1870s. The code used 5 bits with start and stop bits. It's limitation is 32 possible combinations.

EBCDIC - Developed by IBM used for synchronous transmission. It is an 8-bit code allowing 256 character representations.

ASCII - Developed by The American National Standards Institute (ANSI), known ANSI standard X3.4 - 1977. ASCII standard can represent 128 characters.