I have installed 20 modems on mobile PCs (emergency car information system with stock Intel D2500CC; wheezy 64bit ).
Most important - update to latest FW.
The VID/PID of the MC7xxx when in QMI mode is 1199/68A2
the VID/PID of the MC7304, by default, is 1199/68C0
I have rule - try to use kernel drivers (modules) and try to avoid any 3rd party install (that’s why I doped Huawei ME909u-521).
So new usbid is a part of new Linux module which support MC7304 with QMI thing. That is supported only from Jessie (NOW).
If you want to use Wheezy kernel, only SIERRA module useful. But Sierra module does not interface with usbid 68A2 (it not listed in module code; lsmod sierra). Now it will support QMI and AT interface.
Sierra modem are complete solution, they don’t need any FW to load from kernel. So kernel driver (module) need only serial connection and driver doe’s not do to much (IMHO).
To apply changes to MC7304 you need Windows (with driver installed) or Jessie. Now you have serial connection to modem:
ttyUSB0 - DM port (not useful for me)
ttyUSB1 - NMEA GPS data (needs blindly “echo $GPS_START > /dev/ttyUSB1” to enable data output)
ttyUSB2 - AT port (modem)
plus bunch of other things.
Can see more output with modem-manager-cli “mmcli -m 0” (under Jessie).
Now you can revert modem to old USBid (from root shell):
echo -e ‘AT!ENTERCND=“A710”\r’ > /dev/ttyUSB2
sleep 1
echo -e ‘AT!UDPID=68a2\r’ > /dev/ttyUSB2
sleep 2
echo -e ‘AT!UDUSBCOMP=6\r’ > /dev/ttyUSB2 (by default it is AT!UDUSBCOMP=7; please read 4114486 AirPrime MC73XX-8805 AT Command Reference.pdf )
sleep 2
echo -e ‘AT!RESET\r’ > /dev/ttyUSB2
(echo is faster then minicom way).
I believe that default setting better suites Windows. “AT!UDUSBCOMP=6” better for Linux kernel.
For me it was useful to read AirPrime_MC73xx_USB_Driver_Developers_Guide_Rev1_1.pdf
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