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Software Upgrade 87
XModem completes transmission by the receiving program (receiver) and the
sending program (sender). In XModem, the transmission begins with the sending
of negotiation characters from the receiver for the purpose of check mode
negotiation. After passing the negotiation, the sender is allowed to send the first
data packet. Upon the receipt of the complete packet, the receiver checks the
packet using the agreed checking mode and will send an ACK if the packet has
passed the check and a NAK if not. Receiving the ACK, the sender will send the
next packet; receiving the NAK instead, the sender will retransmit the previously
sent packet.
2 Xmodem application
Step 1: In the Boot menu, enter 4, press Enter, and the system will access the
serial interface submenu:
SERIAL SUBMENU
1. Download file to SDRAM through serial interface and boot
2. Download file to Flash through serial interface
3. Download file to HardDisk through serial interface
4. Modify serial interface boot parameter
0. Return to main menu
Enter your choice(0-4):4
Step 2: Enter 4 in the serial interface submenu and press Enter to access the
following interface for setting the parameters of the downloading serial interface:
1: 9600(default)
2: 19200
3: 38400
4: 57600
5: 115200
please select an appropriate baudrate:
Enter your choice(1-5): 5
Step 3: Select the appropriate downloading speed as needed. For example, enter 5
to select the downloading speed of 115200 bps, press Enter, and the system will
display the following information in the terminal:
BaudRate is 115200 bps. Please change the terminal’s speed to 115200
bps
Step 4: At the prompt displayed in the last step, change the baud rate on the
Console terminal to the same one selected for software downloading, disconnect
the terminal and connect it again, press Enter, and the terminal will access the
serial interface submenu again:
SERIAL SUBMENU
1. Download file to SDRAM through serial interface and boot
2. Download file to Flash through serial interface
3. Download file to HardDisk through serial interface
4. Modify serial interface boot parameter
0. Return to main menu
Enter your choice(0-4):2
n
■ After changing the baud rate, you must close the terminal emulation program
and start it again for at least once in order to validate the new baud rate.
■ In a Windows 98 operating system environment, you can perform the
operations of disconnection and reconnection after changing the baud rate. In
a Windows 2000 operating system, however, you must disconnect the terminal
before setting the baud rate and connect the terminal after finishing the work.