2022 California Standards for Accessible Design Guide (effective January 1, 2023)

11B-411.2.1.5 Button requirements.

Keypad buttons, the accessibility function button, and additional hall call console buttons shall comply with Section 11B-411.2.1.5.

11B-411.2.1.5.1 Size.

Buttons shall have square shoulders, be 3/4 inch (19.1 mm) minimum in the smallest dimension and shall be raised 1/8 inch (3.2 mm) plus or minus 1/32 inch (0.8 mm) above the surrounding surface. The buttons shall be activated by a mechanical motion that is detectable.

11B-411.2.1.5.2 Color.

Characters and symbols on buttons, where provided, shall be white on a black background.