My mobile carrier is GSM hybrid 900/1800 for voice and SMS. Is there a way to know (even if it's a dbus query I don't care) which GSM band I'm currently using in the N900?

I'm asking because I'm curious, the 1800 MHz cells are supposed to be better (or so my carrier says). I'd want to know which one I'm using and a way to force the registering in another band would also be nice.

I used to have a Palm Treo 650 and there was a way to force a specific GSM band on it.

Please bear my 8-years-old grammar and bad english (it's not my native language).