3G USB modem switches back to storage mode after connection is lost

Question

I configured a 3G modem (Novatel Wireless U679 (Ovation MC679)) on a Raspberry Pi running Raspian OS. To switch the modem from storage mode (1410:5059) to modem mode (1410:7031), I use the following command:

sudo eject /dev/sr0

I then use Sakis3G script to establish the connection with:

sudo /usr/local/bin/sakis3g/sakis3g connect OTHER="USBMODEM"     
USBMODEM="1410:7031" USBINTERFACE="0" APN="crstat.bell.ca" APN_USER="0"  
APN_PASS="0" USBDRIVER="option"

I also use UMTSkeeper to keep the connection alive if this one drops.

The 3G connection lasted 2 days before dropping for the first time and then never reconnected. When I tried to reconnect manually by reissuing the above sakis3g command, I got the following answer:

Already selected value USBMODEM="1410:7031". Is not valid.

So I typed 'lsusb' at the command line, I saw that the modem product ID was back to storage mode (1410:5059). If I try to switch it again to modem mode using the command 'eject', this time the modem disappear from the 'lsusb' list.

Here are my questions:

1 - Why the product ID switches back to storage mode after a connection drop?

2 - How can I switch it again to modem mode after a connection drop?

3 - How does these steps integrates with UMTSkeeper so that it reconnects automatically?

Answer 1

i am not sure what exactly is the problem.. but i too had this issue. In my case the raspberry pi doesn't switch automatically so i had to use a command to switch it. the command i used was :

         " sudo ./sakis3g swithonly "

it switches the dongle from storage mode to modem mode and i don't face any problem like that of yours. my dongle remains in modem mode even if disconnect the connection. it goes back to storage mode only if i unplug and then re-plug.

Hope this helpful!