3com 4210G Manual De Usuario

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5-3 
 
The loading process of the Boot ROM software is the same as that of the host software, except that 
during the Boot ROM loading process, you must enter the different digit after entering the Boot Menu 
and the system gives somewhat different prompts. The following text mainly describes the Boot ROM 
loading process.  
 
Loading Software Using XMODEM Through Console Port 
Introduction to XMODEM 
XMODEM is a file transfer protocol that is widely used due to its simplicity and good performance. 
XMODEM transfers files via console port. It supports one type of data packets (128 bytes), two check 
methods (checksum and CRC), and error packet retransmission mechanism (generally the maximum 
number of retransmission attempts is ten).  
The XMODEM transmission procedure is completed by the cooperation of a receiving program and a 
sending program. The receiving program sends a negotiation packet to negotiate a packet check 
method. After the negotiation, the sending program starts to transmit data packets. When receiving a 
complete packet, the receiving program checks the packet using the agreed method. If the check 
succeeds, the receiving program sends an acknowledgement packet and the sending program 
proceeds to send another packet; otherwise, the receiving program sends a negative 
acknowledgement packet and the sending program retransmits the packet.  
Loading Boot ROM software 
Complete the following tasks to update the Boot ROM software using XMODEM through the console 
port (For details about the HyperTerminal, refer to 
): 
Task 
Remarks 
Required 
Log in to the switch through the HyperTerminal 
and then configure the protocol used for loading 
files. 
Required 
Log in to the switch through the HyperTerminal 
and then set the download rate of the console port 
on the switch. 
Optional 
Set the baud rate of the serial port on the terminal 
to be consistent with that of the console port on 
the switch. 
Required 
Transmit a file from the terminal to the switch, and 
update the Boot ROM file on the switch. 
Optional 
Set the baud rate of the serial port on the terminal 
to be consistent with the default rate of the 
console port on the switch.