Term used for recording spoken ‘take’ numbers or cues on tape by analogy with the chalked numbers on a film clapperboard.
"Great work with tape to CD! Thank you for doing a wonderful job in transferring our tape to CD. It came out better than we expected. The imperfections of the tape are noted, and your attention to detail appreciated, but are not a problem for us. We wish you the best of success in your business which I am sure a lot of people need but are not ..."