Dear friends, I am facing almost same issue of disconnecting, I have purchased this modem around Jan and never used this, now I moved to Hosur and I purchased a 3G SIM from BSNL, I started using it and now I am getting device disconnected after 5-10 seconds and modem is getting restarted and I am getting error "The SIM/USIM has not been detected or is invalid" and its automatically detecting after sometime, I changed the setting to GSM network and its working fine connected at 236.8kbps without any disconnection, any solution for this?.