On a recording console, a two position switch which allows any input module to be assigned to a microphone in the studio, or to a previously recorded track on a tape recorder.
"Just a note to say thank you so much, for doing such a great job ! My husband and I made this 8-Track tape in 1975, which was 35 years ago. We had given up on trying to get it restored, and then I found your website. Now, we can give copies to our children and grandchildren. It turned out much better quality than we could ever have hoped for. ..."