The 723642 is a monolithic Bidirectional SyncFIFO (clocked) memory. Two independent 1K x 36 dual-port SRAM FIFOs on board each chip buffer data in opposite directions. Communication between each port may bypass the FIFOs via two 36-bit mailbox registers. Each mailbox register has a flag to signal when new mail has been stored. The enables for each port are arranged to provide a simple bidirectional interface between microprocessors and/or buses with synchronous control.