Those patterns might be either directly consumed by humans (through reading, viewing, etc.) or may be used to operate other devices such as a cassette player or a computer.
Digital audio players shaped as cassettes have also become available, which can be inserted into any cassette player and communicate with the head as if they were normal cassettes.
Previously optional items that were now added as standard equipment included a cassette player with graphic equalizer, remote fuel filler door release, and a front license plate mounting.
As radios became tightly integrated into dashboards, many cars lacked even standard openings that would accept aftermarket cassette player installations.
