A digital perm is a perm that uses hot rods with the temperature regulated by a machine with a digital display, hence the name. The process is otherwise similar to that of a traditional perm. The name “digital perm” is copyrighted by a Japanese company, Paimore Co. Hairstylists usually call it a “hot perm.”
A normal perm basically requires only the perm solution. A digital perm requires a (different) solution plus heat. This type of perm is popular in several countries, including South Korea and Japan.
The wonderful salon that I went to can be found here.