EM7355 - cannot get NMEA working


Using Linux and an EM 7355 device which is configured to USB mode 8 which is:

  • DIAG (ttyUSB0)
  • NMEA (ttyUSB1)
  • AT (ttyUSB2)
  • MBIM

I can open the AT interface and get GPS fix and also the location using the AT commands but I cannot see anything when I open the serial port for the NMEA interface. I have used 115200, 8, 1, None. I was expecting to see NMEA sentences but it is dead quite.

Any ideas what I do wrong?


I haven’t tried this on anything newer than an MC7710, but there you have to use the “well known” Qualcomm trick to start NMEA:

echo "\$GPS_START" > /dev/ttyUSB1
     # use GPS
     echo "\$GPS_STOP"  > /dev/ttyUSB1

ref thinkwiki.org/wiki/Qualcomm_Gobi_2000

Thanks. Now it works.