After sending a command (e.g. getio) the device keep sending the IO status. There is no regular pattern, but it keeps sending.
Connecting to the configurator the "Sent SMS" counter is incrementing according with the number of SMS sent, the Received SMS is incrementing as well despite the fact no one sent any SMS. It's like the device does not understand that such SMS was already replied.
Testing on a FMB1225 works just fine.