Boot ROM

Boot ROM (Flash ROM)
For Boot ROM, the flash ROM of 1 Mbytes(512 Kbytes × 2 EA) is used. Boot ROM has the program for the initial operation of system(system operation program), and performs the downloading the main program from the flash ROM, which is the Smart Media Card into the SDRAM.
128 Mbytes(Extension into 256 Mbytes can be made) are basically to the 256 SDRAM, and is composed of four 32Mbytes elements. SDRAM has the main program resident to operate, and saves the data necessary for processing the system. In addition, SDRAM is designed to operate in No Wait for the maximum performance of the system.
2 Mbytes are provided to SRAM, and is composed of two 1Mbytes element. SRAM can perform the memory backup, and saves the various DB information. The various DB information necessary for the system operation are to be saved at SRAM, but they should be always saved also at the smart media. By doing so, the DB information can be safely saved even when the system is critically damaged from the outside.
NAND_FROM is composed of 512 Kbytes, and is used as the subsidiary memory device of OS-7400 system. It saves various DB information.
Smart Media
Smart media is the NAND flash memory card that has saved the main program(OS) for operating MP40 at itself. In addition, is is used as the auxiliary memory of OS-7400 System. The currently used smart media is 32 Mbytes, and 8-bit parallel bus connection mode is used for the connection to the system, which can be used without the change of hardware even though the capacity increases(But the change of the software is needed.) Smart media should operate always with itself mounted on the system, and should be saved in the vinyl packed when the card is delivered.
The engine of MP40 uses one of Samsung ASIC. If the extension rack connected to MP40 is LCP, the engine provides the function by which the individual compensation for the voice signal connected by the subscriber card is made.