The A-to-B enable (CEAB) input must be low in order to enter data from A or to output data to B. Having CEAB low and LEAB low makes the A-to-B latches transparent; a subsequent low-to-high transition of LEAB puts the A latches in the storage mode. With CEAB and GAB both low, the 3-state B outputs are active and reflect the data present at the output of the A latches. Data flow from B-to-A is similar, but requires the use of CEBA, LEBA, and GBA inputs.