The Facing Identification Mark, or FIM, is a bar code designed by the United States Postal Service to assist in the automated processing of mail. The FIM is a set of vertical bars printed on the envelope or postcard near the upper edge, just to the left of the postage area (the area where the postage stamp or its equivalent is placed). The FIM is intended for use primarily on preprinted envelopes and postcards and is applied by the company printing the envelopes or postcards, not by the USPS.
The FIM is a nine-bit code consisting of ones (vertical bars) and zeroes (blank spaces). The following four codes are in use:
FIM A: 110010011
FIM B: 101101101
FIM C: 110101011
FIM D: 111010111
The FIM serves the following purposes. It allows the proper facing of mail for cancellation. It also identifies the manner in which postage is paid (e.g., business reply mail or Information Based Indicia (IBI) postage) and whether that business reply mail has a POSTNET bar code. If the POSTNET bar code is present, the mail can be sent directly to a barcode sorter.