Cylindrical And Mortise Lock Functions  A lock is designated as
a part number, name and an ANSI “F” (function) standards
reference number where applicable. The manufacturer determines
the lock part number and name. Most lock names describe their
operation. For example, a Sargent Lock 11G30, Communicating Lock
has the ANSI function number F80. Not every manufacturer will
make all of the ANSI function number locks.  Every ANSI function
number has a description, much like the operation. The function
numbering began with mortise locks. The ANSI F01 Passage Mortise
Lock description for Marks USA is “Latch by knob/lever either
side.” The Sargent Lock description for the ANSI F01 Passage or
Closet Mortise Lock function description is “Trim from either
side retracts latch bolt at all times.” Both say the F01
function mortise locks do not have keyed cylinders or a
deadbolt, and the inside or outside knobs or levers will retract
the latch at all times.  Because of the number of mortise lock
functions, most lock manufac