Westinghouse AE

These buttons were used by Westinghouse in the 60s and 70s. Most of the time, these fixtures are just referred to as "AE" but there are actually both type "A" and type "E" fixtures.

Type A

This style of button from the front is a flush button, meaning that it is overall flat with the rest of the panel. This particular video shows the wiring of a type A call button.