User`s guide

Performing Diagnostics 13 - 7
Downloading Using Xmodem Protocol (Xmodem/Crc-xmodem)
Use the Xmodem or CRC-xmodem options to load the new firmware ver-
sion through the Console Port.
Depending on the communications software programs available, choose:
n Xmodem: Terminates packets with a “checksum”
n CRC-xmodem: Terminates packets with a Cyclic Redundancy
Check (CRC).
è To load firmware using Xmodem or CRC-xmodem:
1. Connect a terminal to the Console Port using a communications
software program (Procomm
TM
or Windows
TM
Terminal).
2. Select either the Xmodem option or CRC-xmodem option, depending
on your communications software.
The following message appears:
Ready for XMODEM download. Use several ^XÕs to cancel
3. Set the communication program to initiate the file transfer to the
unit.
4. The unit begins the file download. A message similar to the follow-
ing appears:
XMODEM: received 160450 bytes in 00:03:36; 800 bytes/s
transfer rate
After the loaded code for the new firmware is validated, the flash mem-
ory is programmed and the unit will restart with the new code.
The firmware consists of the boot block and the application code. Dur-
ing the firmware download, the application code is replaced, but the boot
block is not.
When the unit powers up, the boot block checks the integrity of the
application code. If it is valid, the boot block will execute the new firm-
ware. If it is invalid, the boot block will display an error message on the
Console and the firmware will need to be reloaded.
The only time you should receive an invalid application code is when
the flash memory device fails or the power is interrupted while the flash
memory is in the process of being programmed.