18-bit machines use a variety of character encodings, including:.
*The [[DEC Radix-50]], (called Radix 50<sub>8</sub> format), packs three characters plus 2two bits in each 18-bit word.<ref>Digital Equipment Corporation, ''PDP-9 Utility Programs--Advanced Software System--Programmer's Reference Manual'', [http://www.bitsavers.org/pdf/dec/pdp9/DEC-9A-GUAB-D_UTILITIES.pdf full text], Digital Equipment Corporation, 1968, Appendix 1.</ref>
* "Teletype" packs 3 characters in each 18-bit word; each character a 5-bit [[Baudot code]] and a upper-case bit.<ref name="pdp7" />
*The [[DEC SIXBIT]] (often called "ASCII")Teletype packs 3three characters in each 18-bit word,; each character a 5-bit [[Baudot code]] and a upper-case bit.<ref name="pdp7" />
The [[DEC SIXBIT]] format packs three characters in each 18-bit word,<ref name="pdp7">[http://bitsavers.trailing-edge.com/pdf/dec/pdp7/PDP-7_AsmMan.pdf "PDP-7 Symbolic Assembler Programming Manual"]. p. 6; p. 38-39.</ref> each 6-bit character obtained by stripping the high bits from the 7-bit ASCII code, which folds lowercase to uppercase letters.
p. 6; p. 38-39.
</ref> each 6-bit character obtained by stripping the high bits from the 7-bit ASCII code, which folds lowercase to uppercase letters.
