Complex sentence: In 1927, GE unveiled a variable-area sound-on-film motion picture sound system based on Hoxie's work; it was marketed by RCA (then a GE subsidiary) as RCA Photophone.
Split into simpler sentences: In 1927, GE unveiled a variable-area sound-on-film motion picture sound system based on Hoxie's work. It was marketed by RCA (then a GE subsidiary) as RCA Photophone.