Cal. Gov. Code § 20426
"Local police officer" also includes any officer or employee of a police department of a contracting agency that is a city, employed to perform communication duties for an employer that contracted with this system for coverage for its local police officers on October 1, 1948, and who elected to become a local safety member on August 25, 1973, pursuant to Chapter 91 of the Statutes of 1973.
This section shall not apply to any contracting agency nor to the employees of a contracting agency until the agency elects to be subject to this section by amendment to its contract made in the manner prescribed for the approval of contracts or, in the case of contracts made after January 1, 1989, by express provision in the contract making the contracting agency subject to this section.
Ca. Gov. Code § 20426