California Code, Penal Code - PEN § 2084.5

(a) A state prison or youth residential placement or detention center operated by the Department of Corrections and Rehabilitation shall provide persons in their custody and confined in a correctional or detention facility with accessible, functional voice communication services free of charge to the person initiating and the person receiving the communication.  The Department of Corrections and Rehabilitation shall have operational discretion in implementing this subdivision such that free voice communication services do not interfere with necessary programming.

(b) A state agency shall not receive revenue from the provision of voice communication services or any other communication services to a person confined in a state correctional or detention facility.