Seeburg, Marquette, Operators, Western Electric, Nelson-Wiggen, and
other American coin pianos and orchestrions had three separate tracker
bar holes devoted to rewind, play (at the end of rewind), and shutoff,
respectively. Roll styles A, G, 4X, H, O, M and others all had these
three holes somewhere in the tracker bar for these three functions.
(Style A rolls happen to have them near the edges, G rolls near the
Wurlitzer pianos and band organs, Weber and most Welte orchestrions
have separate holes for rewind and shutoff, but no hole for play at
the end of rewind. Instead, there is a mechanical finger that falls
into a slot cut partway around the take-up spool when the V-shaped
leader begins to come off the spool.
Hupfeld instruments use a combination of three or four holes at the
end of the roll to operate a little pneumatic "adding machine" to put
the instrument in rewind. These are holes that, individually, have
musical functions but never occur simultaneously within the music.
A mechanical finger senses the end of rewind and shifts the instrument
back into play, and a different combination of holes causes the
instrument to shut off. This makes all holes in the tracker bar
available for musical functions, with none "wasted" just for
roll-handling functions. Various Hupfeld instruments -- Helios, Pan
Orchestra, Phonoliszt-Violina, etc. -- each has its own roll size,
hole spacing and hole combinations.