I just got my second Telit GSM862 Quad module and I could not get it to work. I could use various AT commands to find out various configurations of the system, but I could not send an SMS message or make a call. Well after going though the entire AT command manual and comparing the configuration of my first module versus the second module, I found out that the reason my new module was not working was that it was factory set to use band 0 (900MHz + DCS 1800MHz) instead of band 1 (900MHz + PCS 1900MHz), after setting the module to use band 1 — AT#BND=1 — the module starting working fine. Clearly, band 1 is the correct setting for US.
But why didn’t the module automatically pick the correct band? After all there is the AT#AUTOBND=1 command that is suppose to pick the correct band. The factory default is to disable automatic band selection. I suspect that the automatic selection consume more power and that is the reason why it is by default turned off.
