Cannot Connect to 5G network

chris_macdonald

We have the 5G Sim card in and the connectivity guide is not working for us. We can start the connection process, but the modem is not connecting to the 5G network.

download (1)-min.png

tom

@chris_macdonald Did you run through rb5-modem-configure ?

chris_macdonald

@tom Yes we did. We tried both carrier and private network and neither worked for us.

tom

@chris_macdonald One note, after running through rb5-modem-configure it'll setup a rb5-modem background service. I recommend disabling that service if you're experimenting with initializing a connection manually: systemctl stop rb5-modem && systemctl disable rb5-modem

Otherwise you may have the same script running twice at the same time.

What cellular provider are you attempting to use?

chris_macdonald

@tom Noted. Stopping and disabling the service before manually running the modem start script appears to have not changed the outcome. Letting the service start it by itself does not seem to work to establish a connection either.

The carrier network we tried was Verizon. We have switched back to our private network.

tom

@chris_macdonald Okay, Verizon is not supported by Quectel. They won't allow a Quectel modem to connect to their network.

Internally we test with GoogleFi (uses TMobile)

chris_macdonald

@tom Gotcha. We had the same issue on our private network that does support Quectel.

tom

@chris_macdonald Okay another thought, we had another customer who needed to unlock their SIM using a PIN in order to enable it: https://forum.modalai.com/topic/783/sim-card-pin-issue-for-lte-v2-module?_=1647023788468

chris_macdonald

@tom Just checked it on a phone and SIM card doesn't seem to have a PIN

Eric Katzfey

@chris_macdonald What band is your private network using?

chris_macdonald

@Eric-Katzfey N41 (2.5Ghz)

chris_macdonald

Are there any forcing options? Can we force the drone to be on 5G only?

tom

There are, however most carriers require an initial connection to 4G and then a handoff to 5G, therefore the modem may not be able to make a connection when setting to 5G only.

By default it is set to both LTE and 5G and will always prefer 5G if it's available.

We set this setting in /usr/bin/set-mode-pref
which sends an AT command to the modem.

chris_macdonald

@tom The link is coming back bad on my end. We will try a different carrier as well.

tom

@chris_macdonald Oops, my bad. It is on board at /usr/bin/set-mode-pref