49 CFR Part 27 - Nondiscrimination on the Basis of Disability in Programs or Activities Receiving Federal Financial Assistance (with amendments issued through Aug. 2015)

(3) Operable parts. Operable parts must comply with section 309 of the 2010 ADA Standards, and the following requirements:

(i) Identification. Operable parts must be tactilely discernible without activation;

(ii) Timing. Where a timed response is required, the user must be alerted visually and by touch or sound and must be given the opportunity to indicate that more time is required;

(iii) Status indicators. Status indicators, including all locking or toggle controls or keys (e.g., Caps Lock and Num Lock keys), must be discernible visually and by touch or sound; and

(iv) Color. Color coding must not be used as the only means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.