Re: better support for EV-DO AC8700 800 M usbserial modem ??

["umesh kernel" <umesh.linuxkernel@gmail.com>]

On Mon, Aug 25, 2008 at 9:19 PM, Greg KH <greg@kroah.com> wrote:
> On Sun, Aug 24, 2008 at 09:41:33AM +0530, ctuxer wrote:
>> hi everyone ,
>>
>> i have been using the EVDO AC8700 modem (usbserial) with kernel 2.6.26.2 ,
>> it uses the 'option' module along with the generic usbserial module . Well
>> i am happy for the improved support for the modem handling in the new
>> kernels( like now i don have to modprobe with the vendor and product IDs )
>> , there is one point specific to this modem which is still not handled ,
>> ..... the modem switches between EVDO and CDMA mode when the signal
>> strength is low or when there is a bandwidth overload at the vendor's( the
>> service provider , bsnl in my case )  tower . This switch in the mode is
>> not recognised by the driver and the connection is lost once this switching
>> occurs . I have to restart the wvdial program to reconnect .
>>
>> But if the modem were in CDMA mode when i connect , then the connection is
>> not lost when the modem switches back from CDMA to EVDO . I really don know
>> enough to understand what is the difference between the two cases or what
>> can be done to improve the support for this usbserial modem , ... can
>> anyone help ?
>
> This looks like something the userspace side has to handle, the option
> driver is just a dumb "pass-through" type driver, it doesn't really
> control the modem at all.  The "control" channel on the modem allows
> this to happen, a userspace program drives this.
>
> good luck,
>
I am using the same EVDO modem, but using KPPP as dialer and using
option module(also tried airprime module after adding the vendor and
product ids ). I am not facing this. issue. Connection is fine when
switching occurs. I can see that whenever modem light turns from
GREEN(EVDO) to Orange(CDMA 1x RTT) or back , only the data rate is
changing but the conenction is fine. Please check with KPPP dialer and
enable the option "Auto reconnect".

Regards,
Umesh