The 72V3663 is a 4K x 36 Sync FIFO that is a 3.3V version of the 723663. 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. The FIFO has Retransmit capability which resets the read pointer to the first memory location. This device can operate in IDT Standard mode or First Word Fall Through mode.