US patent 3946220, William M. Brobeck; John S. Givins Jr. & Philip F. Meads Jr. et al., "Point-of-sale system and apparatus", published 1976-03-23, assigned to Transactron, Inc.[1]
US patent 3946220, William M. Brobeck; John S. Givins Jr. & Philip F. Meads Jr. et al., "Point-of-sale system and apparatus", published 1976-03-23, assigned to Transactron, Inc.[1]