DT8xM series is fantastic; with simple steps you are able to quickly setup a data connection. On field the integrated diagnostic done via the integrated keypad and display makes life easier in antenna positioning and network checking. For a dial in solution I would suggest a couple of GSM modems. DeLoad software may be programmed to do the unload operation with the required frequency. In some countries (my country at least) is becoming harder to get the "data number" over the GSM connection since the mobile operator are dismissing this technology in favor TCP/IP based solutions, so if today this approach works for tomorrow no guarantee... So in my opinion if a couple of GSM modems are buried in warehouse, an attempt in getting two SIMs with dial data number (and low or flat rate...) worth the effort, otherwise not.