To do this you

1. Need a TFTP server running (solarwinds)
2. Need to telnet into the device
3. Need to be in enable mode

First to make the backup:

write net 192.168.1.2:MyBackup.pixconfig

where the IP is the IP of your TFTPserver

Then to restore it later, you need to enter config terminal mode first and then restore the file:

config term
configure net 192.168.1.2:MyBackup.pixconfig

and there you have it…

The changes will take immediate effect, but you will still need to write them into the non volatile memory, or the changes will be lost when you reboot the device.