List of Binary Codes - Five-bit Binary Codes

Five-bit Binary Codes

A number of different five-bit codes were used for early punched tape systems.

Five bits per character only allows for 32 different characters, so many of the five bit codes used two sets of characters per value referred to as FIGS (figures) and LTRS (letters), and reserved two characters to switch between these sets. This effectively allowed the use of 60 characters.

The following early computer systems each used their own five-bit codes:

• J. Lyons and Co. LEO (Lyon's Electronic Office)
• English Electric DEUCE
• University of Illinois at Urbana-Champaign ILLIAC
• ZEBRA
• EMI 1100
• Ferranti Mercury, Pegasus, and Orion systems

More general five-bit standard codes are:

• International Telegraph Alphabet No 1 (ITA1) - Also commonly referred to as Baudot code
• International Telegraph Alphabet No 2 (ITA2) - Also commonly referred to as Murray code
• American Teletypewriter code (USTTY) - A variant of ITA2 used in the USA
• DIN 66006 - Developed for presentation of ALGOL/ALCOR programs on paper tape and punch cards

Finally, the steganographic code commonly known as Bacon's cipher uses groups of 5 binary valued elements to represent letters of the alphabet.