02-04-2022, 09:33 AM
The modem presents multiple USB ports with different uses. IIRC ttyUSB1 is NMEA output only, while ttyUSB2 is used for the AT commands that control it. Some modem failure modes cause one or more of the USB ports to disappear until the modem is restarted. You don't mention whether you're checking the NMEA output to see if it's getting a fix before you start gpsd. I don't know if the AGPS is now handled automatically or whether you'll need to do that manually, but without it you need a clear sky view, patience and luck to get a fix at all. Some people have trouble getting a fix even with the AGPS working. I don't remember what I did to get gpsd working while ModemManager was running - I'll see if I can find anything in my notes.