[[FIELDATA]] was a seven-bit code (with optional parity) of which only 64 code positions (occupying six bits) were formally defined.<ref name="Mackenzie_1980">{{cite book |title=Coded Character Sets, History and Development |work=The Systems Programming Series |author-last=Mackenzie |author-first=Charles E. |year=1980 |edition=1 |publisher=[[Addison-Wesley Publishing Company, Inc.]] |isbn=0-201-14460-3 |lccn=77-90165 |page=64 |id={{ISBN|978-0-201-14460-4}} |url=https://books.google.com/books?id=6-tQAAAAMAAJ |access-date=2016-05-22}}</ref> A variant was used by [[UNIVAC]]'s 1100-series computers.<ref name="Walker_1996">{{cite web |title=UNIVAC 1100 Series FIELDATA Code |work=UNIVAC Memories |author-first=John |author-last=Walker |date=1996-08-06 |url=https://www.fourmilab.ch/documents/univac/fieldata.html |access-date=2016-05-22 |url-status=live |archive-url=https://web.archive.org/web/20160522120813/https://www.fourmilab.ch/documents/univac/fieldata.html |archive-date=2016-05-22}}</ref> Treating the code as a six-bit code these systems used a 36-bit word (capable of storing six such reduced FIELDATA characters).<ref name="Jennings_2016">{{cite web |title=An annotated history of some character codes or ASCII: American Standard Code for Information Infiltration |author-first=Thomas Daniel |author-last=Jennings |author-link=Thomas Daniel Jennings |website=World Power Systems (WPS) |date=2016-04-20 |orig-year=1999 |url=http://worldpowersystems.com/J/codes/#FIELDATA |access-date=2016-05-22 |url-status=live |archive-url=https://web.archive.org/web/20160522024759/http://worldpowersystems.com/J/codes/#FIELDATA |archive-date=2016-05-22}}</ref>
