Brett, You need a copy of IEEE STD-200-1975 / ANSI Y32.16-1975 which describes ref des assignment methods, available through the American National Standards Institute, Inc.
You will also need ANSI/IEEE Std 315A-1986, which displays the symbols and lists
the class designation letters.

Clifford H. Lamson                      phone: 407-727-5158
Designer 3 / CADD Group Leader          pager: 407-690-8594
Harris G.A.S.D., MS22/4842              fax:   407-727-4430
P.O. Box 94000                          email: [log in to unmask]
Melbourne, FL 32902                     smtp:  [log in to unmask]

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