thank you your reply
yes the n810 can use the web by m620's hsdpa.
and i did your suggestion of setting like 256colors, no sound etc.
but doesn't works

you are right, i also think more bandwidth needs.
so it's my problem, the n810 doesn't recognize m620's 801-11g (the wireless band type, not 11b) my device only 11b,not 11g when i connect the m620.
the other ap is ok...

thank you.