2016 California Standards for Accessible Design Pocket Guide - Eff. Jan. 1, 2017

11B-411.1.2 Car designations.

Elevator cars shall be designated with a single alphabetic character. For elevators programmed to the same hall call console or group of hall call consoles, each elevator car shall be designated with a different single alphabetic character.

Exception: Elevator systems with more than 26 elevators shall be permitted to use alphanumeric designations such as “A1”.