The MC74AC640/74ACT640 octal bus transceiver is designed for asynchronous two-way communication between data buses. The device transmits data from bus A to bus B when T/R = HIGH, or from bus B to bus A when T/R = LOW. The enable input can be used to disable the device so the buses are effectively isolated.
   
• Bidirectional Data Path
• A and B Outputs Sink 24 mA/Source –24 mA
• ′ACT640 Has TTL Compatible Inputs