One of its most remarkable innovations was the pneumatic changer mechanism.
Many of the machine’s functions were controlled not mechanically or electrically but by air pressure.
This system made it possible to automatically select and play multiple records.
With eight selections on 78-rpm shellac records, the Selectraphone already offered a notable music selection for its time.
The pneumatic mechanism was developed by Axel F. Larson and Charlie W. Anderson.
It was later also used in the Seeburg “Audiophone” introduced in 1928, an important early commercial jukebox.
The technology illustrates how intensively engineers were working on automatic music systems during the 1920s.
The Selectraphone is therefore considered an important precursor of the modern jukebox.