How do you know if you're capped?
From my experience and if you have a TelkomInternet account:
First thing you will notice is that you can not authenticate, you will not be able to connect to the internet, when you enter your username and password when trying to establish an internet connection, you will just get an error.
To make sure, you can then try the following from a PC that has an internet connection (from work or a friend):
Try logging on to the Telkomsa.net usage site (http://adsl.telkomsa.net/)
then
Try logging on to the Saix usage site (http://userstats.adsl.saix.net/)
If you can log in at the telkomsa.net site, but you can not log in at the saix site, you are capped.