A brief history of credit cards - Nidhi Upadhyaya

https://vid.freedif.org/w/rXpdZk5J9QFY2oDfTrLQd5

Learned that the credit card checksum had a mechanical means of calculating the checksum... I can't find the machine anywhere, but it's pretty cool to see that people back in the days had a way of verifying credit card numbers without a computer

https://worldwide.espacenet.com/patent/search?q=pn%3DUS2950048A

#Mechanical #computer #computing #programming #MechanicalChecksum #RetroTech #CreditCardHistory #VintageTech #OldSchoolVerification #TechNostalgia #IngeniousDesign #TechHistory #MechanicalComputing #VerificationTech