Developing a project that uses GM862 Telit module, I have find out that the sms that are not received, goes to the service center, where they are stored and not always are being send back to us when we are reachable! Sometimes these are put in a black-list, other times these are just not being send! The problem is the GSM protocol, it seems it is like a bug! When a terminal reconnects to the network, the network does not notice the reconnection, therefore we must make our presence noticed.