this is what i did for my DSL-502T
install the software tht comes bundles with it
and then open IE and enter the homepage i.e. *192.168.1.1
go to the advanced tab and click on ATM VCC
go to PVC3 change the VCI number to 40 from 35
and then go to PVC0 and start enterin the details
check this image...ur a/c name and password will be different ...lol
*img140.imageshack.us/img140/3672/untitled111am3.jpg
and yes the default username and password to enter the modem's menu is
username: admin
p/w : admin