Black facsimile transmission
In telecommunication, the term black facsimile transmission has the following meanings:1. In facsimile systems using amplitude modulation, that form of transmission in which the maximum transmitted power corresponds to the maximum density of the subject.
2. In facsimile systems using frequency modulation, that form of transmission in which the lowest transmitted frequency corresponds to the maximum density of the subject.
Source: from Federal Standard 1037C and from MIL-STD-188
