12.5 Letter Sign (Indicator) Used in Letter/Number Combinations [II.12.a(1)]

A letter sign distinguishes a letter from a number in a letter/number combination. Whenever a single letter (capitalized or uncapitalized) and a number are connected by a hyphen, a letter sign is needed before the letter to prevent it from being read as another number or as a whole-word contraction. Examples:

3-c3-C c-3C-3