RCA Photophone Wall Plaque
RCA Photophone Plaque
The earliest "talkies" (sound movies) relied on the Western Electric Vitaphone system (circa 1926) which used disk records that were (hopefully) synchronized with the action on the screen.  It was only with the inclusion of an optical sound track on the film that the true sound movie was created. 

Western Electric was the pioneer in this field, both with the Vitaphone system, and their slightly later sound-on-film system. RCA entered the field in 1928 with their own sound-on-film system which they called "Photophone".

These two companies were in fierce competition for the theatre sound business throughout the 1930's. 

Whenever a sound system was installed in a theatre, and especially when it replaced the competitor's system, a plaque such as this one was mounted on a wall in the lobby, or on an outside wall where the patrons would be sure to see it. 

The plaque shown here is believed to be from the mid 1930's, and is a bronze casting about 8 inches in diameter.