A computerized work station that lets quadriplegics manipulate a mechanical arm and operate a personal computer by speaking commands will mean jobs for many paralyzed people, the manufacturer says.

Architecture, engineering, law and small-parts assembly are among the possible jobs quadriplegics could do with the $50,000 "Command 1" work station, said Walter Weisel, chief executive officer of Prab Command, Inc. of Kalamzaoo, Mich."Here's a system that costs less than a Mercedes, we can deliver it in weeks and it puts you back on the payroll," Weisel said.

The system lets a quadriplegic make telephone calls and tap computers and data bases around the world, record telephone messages, operate the desktop computer for accounting and other purposes, and perform a variety of other tasks for home and workplace, the company says.

It was introduced Thursday with a demonstration by Rick Walsh of Seattle, a 50-year-old quadriplegic who was paralyzed 11 years ago and calls himself a computer illiterate.

Speaking into a headset, Walsh said, "Keyboard. Robot. Get Lotus. Keyboard."

At his side, a tan mechanical arm like those that hold up the lamp in a dentist's office whirred quietly and fetched a book from a shelf, presenting it to him.

"Stick Lotus. Keyboard," Walsh said. The arm put the book back. Walsh said he had about three hours of training before the demonstration.

Similar systems have been developed in university laboratories, said K.G. Engelhardt, director of the health and human services robotics laboratory at Carnegie-Mellon University in Pittsburgh. But she said she knew of no other such system now on the market.

Turning the research into a product is "a very, very important step and a difficult one," she said in a telephone interview. "I'm really very pleased that it's happening."

To use the system, a quadriplegic must be able to see well enough to read and to pronounce words or make consistent utterances in place of ordinary words, Weisel said.

He estimated that perhaps half the nation's quadriplegics - people paralyzed in all four limbs - could use it.

Some 140,000 Americans are quadriplegics because of spinal cord injury, said Thomas Stripling, associate director for health studies and analysis at the Paralyzed Veterans of America. The total may be about 600,000 if one adds people with quadriplegia from other conditions such as cerebral palsy, multiple sclerosis and severe arthritis, he said in a telephone interview.