Telit GPRS Module never returning and never timing out for command AT#FTPOPEN
The issues were:


Pin 9 MSM_nRESET should be explicitly set to HIGH.
Pin 10 (DTR) and pin 11 (RTS) should be explicitly set to LOW.
The Nimbelink device requires 5V external power. With USB power, the modem can intermittently reset during period of high activity. If the modem resets, then the command can appear to run forever when nothing is actually running.
Must use FTPOPEN with connection type 1 (passive).