From LQWiki

EBCDIC (Extended Binary Coded Decimal Interchange Code) was an alleged character set used on IBM dinosaurs. It exists in at least six mutually incompatible versions, all featuring such delights as non-contiguous letter sequences and the absence of several ASCII punctuation characters fairly important for modern computer programming languages (exactly which characters are absent varies according to which version of EBCDIC you're looking at). Because of this, it is sometimes jokingly referred to as an encryption scheme. IBM adapted EBCDIC from punched card code in the early 1960s and promulgated it as a customer-control tactic (see connector conspiracy), spurning the already established ASCII standard. Today, IBM claims to be an open-systems company, but IBM's own description of the EBCDIC variants and how to convert between them is still internally classified top-secret, burn-before-reading. Hackers blanch at the very name of EBCDIC and consider it a manifestation of purest evil. See also fear and loathing.

To convert from EBCDIC to ASCII, you can use dd with the conv=ascii or conv=ibm switch, depending on which EBCDIC version you use.

This article is based, in whole or in part, on entry or entries in the Jargon File.