To residents of Seattle and Tacoma, Wash., the sounds coming from their radios once a week deliver unusual information -- computer software. Using a special device, listeners convert the radio signals into digital information for their computers.

Microperipheral Corp., of Redmond, Wash., doesn't believe retail stores are the only way to get software to consumers. The company is producing a half-hour radio program on computer topics, highlighted by short transmissions of software that usually last from 2 to 20 seconds. One station in Seattle and another in Tacoma broadcast the program weekly, and Microperipheral expects to reach more than 1,200 stations nationwide this year through satellite transmission. Microperipheral also transmits software to cable subscribers in the Seattle metropolitan area.

The free software isn't always the sophisticated kind. Microperipheral chooses from the 35,000 or so public-domain programs that are given away by hackers. In the future, the company hopes to entice major software houses to use its radio shows as a marketing tool to reach computer owners at home, where they can try out a sample encrypted program. If they like it, consumers could either buy the program or purchase a password that enables them to fully use the program recorded off the air.

The quality of the software may determine the success of the venture. "If the quality of the transmission is poor, or junk software is transmitted, people will be turned off," says Donald Aronson, an independent consultant.