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.
( 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 ) ) ) ) ) ) . ) ) ) )
(ROOT (S (RB Only) (PP (IN after) (NP (NP (DT a) (JJ common) (NN convention)) (PP (IN for) (NP (NN bar))))) (NP (NNS codes)) (VP (VP (VBD had) (VP (VBN been) (VP (VBN established)))) (CC and) (VP (PP (IN in) (NP (NP (NN use)) (PP (IN for) (NP (JJ several) (NNS years))))) (VBD did) (NP (NNS retailers) (NN turn)) (PP (TO to) (NP (JJ such) (NNS systems))) (S (VP (TO to) (VP (VB transmit) (CC and) (VB receive) (NP (NNS data)) (PP (IN from) (NP (NNS suppliers)))))))) (. .)))
Retailers chose to adopt these systems before a common convention existed for bar codes.
( Retailers ( ( chose ( to ( ( adopt ( these systems ) ) ( before ( ( a ( common convention ) ) ( existed ( for ( bar codes ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Retailers)) (VP (VBD chose) (S (VP (TO to) (VP (VB adopt) (NP (DT these) (NNS systems)) (PP (IN before) (NP (NP (DT a) (JJ common) (NN convention)) (VP (VBN existed) (PP (IN for) (NP (NN bar) (NNS codes)))))))))) (. .)))