I have begun cellular tests of new units of Digi ConnectPort X4 and Digi TransPort WR21, both of which include a GOBI 3000 cellular module. This means if I select AT&T and reboot, it 'converts' the radio to use AT&T compatible frequencies and firmware, while if I select Verizon or Sprint, it 'converts' to work with those networks.
Okay, what is the catch?
- Modest cost increase. I'm not sure what, but the GOBI module requires a fairly large FLASH to hold multiple firmware images, plus special radio hardware.
- Slower reboots - so say some customers. Since the cell module has more software-controlled hardware, it does take longer to start up. I have not done any testing here, but eventually I will produce some numbers.
Digi Support Documentation: Gobi 3G Cellular Carrier Conversion Guide
Digi is also working on a Python script which can be used with a 'test unit' activated on multiple networks (for example, the 3 big ones). The script can be run for a few days and records various statistics - radio strength, connection delays, upload throughput. This will be very useful for a customer with perhaps 100 sites to install, and they have reason to believe that no single carrier will be available at all 100 sites.