These are the setting for the modem used with StarHub Adsl for office use.
VPI/VCI = 0/33
The most important thing is that it is PPPoA and not PPPoE.
Now if we what to use the modem with PPPoA and still get the public ip on our router, here is a possible solution from the following website.
LI commands: (Telnet into modem e.g. with puttY, default password is "Administrator" and password is blank. Case sensitive!)
=>:ppp relay flush
=>:atm phonebook flush
=>:atm phonebook add name=BrPPPoA_ph addr=0.33
=>:service system modify name=PPTP state=enabled
and then I followed the Pdf Config guide at
[7.1.2 Configuration Procedure for Routed PPPoA with DHCP spoofing]
The pdf is attached here.