California Code, Health and Safety Code - HSC § 1797.53

“Alternative base station” means a facility or service operated and directly supervised by, or directly supervised by, a physician and surgeon who is trained and qualified to issue advice and instructions to prehospital emergency medical care personnel, which has been approved by the medical director of the local EMS agency to provide medical direction to advanced life support or limited advanced life support personnel responding to a medical emergency as part of the local EMS system, when no qualified hospital is available to provide that medical direction.