The 74ALVCH16543 is a dual octal registered transceiver. Each section contains two sets of D-type latches for temporary storage of the data flow in either direction.

Separate latch enable (nLEAB, nLEBA) and output enable (nOEAB, nOEBA) inputs are provided for each register to permit independent control in either direction of the data flow.

The 74ALVCH16543 contains two sections each consisting of two sets of eight D-type latches with separate inputs and controls for each set. For data flow from A to B, for example, the A-to-B enable (nEAB) inputs must be LOW in order to enter data from nA0 to nA7, or take data from nB0 to nB7, as indicated in the function table. With nEAB LOW, a LOW signal on the A-to-B latch enable (nLEAB) input makes the A-to-B latches transparent; a subsequent LOW-to-HIGH transition of the nLEAB signal stores the A data into the latches. With nEAB and nOEAB both LOW, the 3-state B output buffers are active and display the data present at the output of the A latches. Similarly, the nEBA, nLEBA and nOEBA signals control the data flow from B-to-A.

Active bus hold circuitry is provided to hold unused or floating data inputs at a valid logic level.