USB Modem issue

[Tommy Trussell]

On Sun, Jan 18, 2009 at 1:30 PM, Sundar Dhanasekaran
<sundar261 at gmail.com> wrote:
> Hi,
>
> I am using USB datacard on my Ubuntu 8.04.  I am able to connect and use
> the internet services.  But when the connection fails, I am not able to
> connect back without rebooting the system.  The modem does not seem to
> be identified.  Not sure why.
>
> Error I get -
>
> --> WvDial: Internet dialer version 1.60
> --> Cannot get information for serial port.
> --> Initializing modem.
> --> Sending: ATZ
> --> Sending: ATQ0
> --> Re-Sending: ATZ
> --> Modem not responding.
>
> $lsusb
> Bus 005 Device 001: ID 0000:0000 Bus 004 Device 001: ID 0000:0000 *Bus
> 003 Device 003: ID 12d1:1001 Huawei Technologies Co., Ltd. E620 USB Modem*
> Bus 003 Device 001: ID 0000:0000 Bus 002 Device 001: ID 0000:0000 Bus
> 001 Device 001: ID 0000:0000
>
> Any pointers on why I have to reboot and how to avoid it?
>
> -Sundar

It sounds like the modem isn't "handshaking" properly, or it doesn't
return to command mode when it should.

You didn't say exactly what model modem you are using, but from your
lsusb dump it looks like you have a Huawei.  I see some Ubuntu
documentation for a Huawei E220
https://help.ubuntu.com/community/DialupModemHowto/Huawei/E220

It looks like the recommended initialization strings are different
from the ones you are using, so you might try making your wvdial
configuration look like the examples -- notice especially the line
that says "Init2 = ATQ0 V1 E1 S0=0 &C1 &D2" -- some of those parts
after ATQ0 are probably important for its correct operation.