I think this topic has been at least partially covered in other threads. The Triumph LS can take a SIM card which is a GSM technology (like I really understand the different systems). In my area, the best coverage is by US Cellular with Verizon a distant second. They are both CDMA technology. AT&T which is the SIM card I have is present, but I rarely see 3g connectivity. What can I use to access our DOT's single vector system? Is a mobile WiFi hotspot the answer? If so, are any models none to play well with our systems?