The logic to setup the generic +CIND indications in the SIM7600E seems
to end up breaking connectivity when in TTY+PPP mode. If we issue the
AT+CMER=3,0,0,1 command, this will end up in the modem not replying a
correct CONNECT response to the ATD command.
Let's disable these +CIND indications completely in the simtech
plugin, as there is even no AT command reference saying those are
supported.
Fixes https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/144
Aleksander Morgado
c98a1a9dc8