The Sierra Wireless EM7455 is a high end cat 6 4G LTE modem that has a whole load of yummy features such as 300 mb per sec download and 50 mb per sec upload speeds .... Here's the FULL SPEC. In the past I have used some 3G and 2G modems, but only every got them to work in GPRS mode, which is fine for sending lots of text via some rather insecure methods such as 'get' or 'post' but not good for uploading spectograph image files to an Amazon server, for example. Another great feature of this device is that's it's extremely compact and slots nicely into a M.2 key B connector.

The device requires a USB carrier board to connect to the Raspberry Pi or Jetson Nano and there's a few possibilities here although we opted for the Linkwave version and bought a high quality antenna on a 10 metre cable at the same time. Ok, it was expensive, but eventually, the results are worth it as being able to send images quickly means less battery juice being consumed.

Connecting to the Raspberry Pi was just a matter of installing 'network manager' and creating a modem connection with the correct APN settings. For my network Three in the UK, the APN was '3Internet' with no password or username. Simple! Getting functionality with the Jetson Nano was a different matter and required doing a live probe on the system drivers being used in the Raspberry pi using:

tail -f /var/log/syslog

 .. run in command line. Eventually i worked out that the most essential driver was qcserial, which is short for 'Qualcomm serial modem', which then had to be enabled in the Jetson Nano kernel .... So with a fresh 128 Gb SD card I flashed the Nano from a host computer using the latest Nvidia SDK Manager package, expanded the file system form 16 Gb to 128 Gb and started messing with the drivers using these these SCRIPTS.