In above web site ; you can select your modem/router and upgrade FW etc.
The full download about 76MB is not counted as usage for anyone ( both limited and U/L)
and d/l at a speed of 200KB/sec
Or you can download a small file to check your modem/system/ speed.
Check the full menu.
Teracom CPE writeSN.exe 583 KB
ZTE CPE FW Upgrade: ZTEFIRMWARE.zip 2 MB
customers using VMC upgrade.exe 4.3 MB
Not many users were happy with the FW Upgrade option etc.
Beginners should not try.
You have to be in PPPoE ( always On) ( Userid/PW stored in modem wan page ).