Really thanks for your reply, the modem can connect to internet follow your configuration.
But the problem for me is can't get the modem to talk to my data logger. FYI, data logger will send modem dial up string over RS232 and establish a PPP session. If successful, it will obtain an ip address, then i can send some data back to my server. so now i am wondering whether this way is working for this modem, haha
FYI, i already enabled RS232 in the modem configuration.