The 723623 is a 256 x 36 unidirectional Sync FIFO memory which supports clock frequencies up to 83 MHz and has read access times as fast as 8 ns. The clocks for each port are independent of one another and can be asynchronous or coincident. The enables for each port are arranged to provide a simple bidirectional interface between microprocessors and/or buses with synchronous control. Communication between each port may bypass the FIFO via two mailbox registers.