EO, or Eight Ones, is an 8-bit EBCDIC

EBCDIC

Extended Binary Coded Decimal Interchange Code is an 8-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems....

 character code represented as all ones (binary

Binary numeral system

The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

 1111 1111, hexadecimal

Hexadecimal

In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...

 FF). It is similar, but not identical, to the ASCII

ASCII

The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

 delete

Delete character

In computing, a delete character is the last character in the ASCII repertoire, with the code 127. Not a graphic character, it denoted as ^? in caret notation and has a graphic representation in Unicode like all ASCII control characters, while its meaning is a bit unclear.There is no common...

 (DEL) or rubout character.

When translated from the EBCDIC character set to code page

Code page

Code page is another term for character encoding. It consists of a table of values that describes the character set for a particular language. The term code page originated from IBM's EBCDIC-based mainframe systems, but many vendors use this term including Microsoft, SAP, and Oracle Corporation...

s with the C1 control code set, it is typically mapped to hexadecimal code 9F, in order to provide a unique character mapping in both directions.