SACRAMENTO, Calif. - A freeway sniper who claimed he was only following commands from ''little communicators'' has been sentenced to a mental hospital for a month-long string of shootings that terrorized motorists.

Christopher Shaw Scalley, who psychologists testified was legally insane when the shootings occurred, pleaded guilty Monday to 10 firearm assaults.

Under a plea agreement, the 49-year-old man will spend at least 19 years of a 23-year sentence in a state mental hospital. He will be required to serve out the remaining time in prison if his sanity is restored.

The sniper attacks terrified motorists on Interstate 80 in the Sierra Nevada foothills for more than a month last summer. The busy freeway is the main east-west link between Northern California and Nevada.

''I wasn't shooting at the people. I didn't want anybody to get hurt. I just wanted to scare them,'' Scalley said.