Does the statement 'Only after a common convention for bar codes had been established and in use for several years did retailers turn to such systems to transmit and receive data from suppliers.' conflict with the idea presented in 'Retailers chose to adopt these systems before a common convention existed for bar codes.'
Only after a common convention for bar codes had been established and in use for several years did retailers turn to such systems to transmit and receive data from suppliers.###Retailers chose to adopt these systems before a common convention existed for bar codes.