OfficeServ 7100 Service Manual© SAMSUNG Electronics Co., Ltd. 2-7SRAM2-Mbyte SRAM is provided and the SRAM consists of two 1-Mbyte elements. The SRAMhas the memory backup function and stores various DB information. However, the DBinformation for the system operation should be also stored in the multimedia card to storedata safely. To do so can store the DB information even if the system is damaged fatallyfrom the outside.Real Time ClockRTC72423 of Seiko is used as the real time clock to provide the system clock.MMC Driver (TE4300)The MMC driver is used for the control the external multimedia card.TE4300 of Tokyo Electronics is used as the MMC driver to connect the CPU interface andthe MMC bus.Multimedia Card (MMC Card)The multimedia card is the NAND flash memory card and is used as the auxiliary storageunit and the voice main file storage. 256-MByte multimedia card is currently used. Since itaccesses the system through the MMC bus in high-speed 1-bit serial bus access mode, itdoes not need the change of the hardware even if the capacity is increased. The card shouldbe always installed to the system for its operation. The card should be wrapped in vinylused in the purchase of the card for the preservation.Internal MusicOne channel is provided for the internal sound source of the system. CODEC supports bothA-LAW method and U-LAW method and the relevant CODEC is operated by the hardwarelogic. The internal sound source is readily changed into an external sound source by usingMMC.Analog Phase Locked Loop (APLL)The OfficeServ 7100 uses an analog PLL. The reference clock of 8 kHz is specified bysoftware. If the external source of the reference clock is not specified, the clock createdinternally is used as the reference clock. The external reference clock of 8 kHz is set by thesystem automatically and a specific board can be specified by using the MMC if necessary.In this case, the specification of the board slot connected the most stable digital line isrequired.Watch DogWatch Dog is the function to restart the system when the system is malfunctioned.The system is designed to be restarted when the system is malfunctioned for a certain time.
