Thank norbi and inquisitor,
'1800' was typo and correct value is '800' (Band VI).
I found
this and confirmed my router may be used.
Japan is a very strange company, as you know. There is no GSM based service. So I would like to know Orange's SIM supports both WCDMA and GSM or there are several types of SIMs; one for WCDMA and another for GSM. This may be stupid question but could anyone tell me about this?
Thanks in advance.