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CTAG

Member

Registered: 2013-10-14

Posts: 82

Sierra WWAN MC8775 not initialized in modem-manager-gui

Hi,

I recently installed an unlocked Sierra MC8775 mini pcie card in my laptop. The card appears to work, but I can't figure out how to properly set it up with either Network Manager or modem-manager-gui.

Checking driver:

$ lsmod | grep sierra
sierra                 20480  0
usbserial              40960  1 sierra
usbcore               208896  9 uvcvideo,usb_storage,ehci_hcd,sierra,uhci_hcd,usbserial,btusb,uas,ehci_pci

$ lsusb | grep -i sierra
Bus 007 Device 002: ID 1199:6812 Sierra Wireless, Inc. MC8775 Device

$ ls /dev/ttyUSB*
/dev/ttyUSB0  /dev/ttyUSB1  /dev/ttyUSB2

The three usbserial devices belong to the card. As I understand it, USB0 is AT-data, USB1 is proprietary, and USB2 is AT-command.

I can open USB2 and manually send an SMS:

$ screen /dev/ttyUSB2
<in screen>
AT
OK
AT+CMGF=1
OK
AT+CMGW="<phone num>"
> Hello?<ctrl-z>
+CMGW: 1

OK
AT+CMSS=1
+CMSS: 20

OK

And the message goes through.

But if I open modem-manager-gui the MC8775 is recognized, and then the UI hangs with an error: "Modem is not ready for operation. Please wait while modem is being prepared..."

On the other side, if I try setting up the device in Network Manager:
- Open 'edit connections'
- 'Add' to create new connection
- Type: mobile broadband
- Select the Sierra device
- Select T-Mobile
- Select USA
- Select any of the internet plans on the drop down.
- Click on the new connection from the taskbar menu, and it eventually fails to connect without any output.

Useful information I've found:
https://wiki.ubuntu.com/SierraMC8775
http://www.developershome.com/sms/howTo … FromPC.asp
https://www.sierrawireless.com/resource … e-v2.4.pdf

Last edited by CTAG (2017-05-09 14:30:12)