This video is from the Vampire Robot YouTube Channel:
https://www.youtube.com/watch?v=XOAv9s1u0qY
Most of it is a family in 1977 shopping at Sears, but at points you can hear the printer of the Singer-Friden cash registers in the background, and at the very end you can see the Singer register in use. The video doesn't show the numeric display very well but you can see the keys light up.
I reposted this because, while there are pictures, I am not sure there is any other video footage online showing the Singer-Friden registers in use.
