The first register designed by the Ritty brothers used a series of disks to store the record of the amount keys depressed.  The maximum amount that could be recorded for each sale was $9.95 and the accumulated total on the disks was viewed through a slot to the left of the fingers. The value of the register was based on the idea that publicity of what was being recorded would force corrections.
The Ritty “Dial Register”

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Paper Roll register
For their second attempt instead of adding disks the brothers designed a series of adding wheels mounted at the back of the machine. Patent number 221360 was granted on the 4th November 1879, it was the first United States patent ever issued for a cash register.