Re: FYI: Emergency calls with MBM modem

[Denis Kenzior <denkenz@gmail.com>]

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Hi Pekka,

On 07/07/2010 08:19 AM, Pekka Pessi wrote:
> Hi all,
> 
> I just did some emergency calls in our lab with the Ericsson MBM modem
> (3507g). The modem firmware has the voice calls enabled, even while
> there is no audio input/output from the modem (as far as I know).
> 
> Main results are:
> - emergency calls are not possible in offline mode (CFUN=4), ATD112;
> returns NO DIALTONE

That was expected, do we have a solution in mind on how to do emergency
dialing in Offline mode?  Is it a UI problem?

> - emergency calls can be made without SIM card (but they require AT+CFUN=1)

That was again expected...

> - most MBM modem functionality (AT+COPS, AT+CLCC does not work without SIM card)

The only one that can be triggered without a SIM card is AT+CLCC.
However, please note that MBM should not be using CLCC, but instead its
own vendor-specific voicecall extensions.

> - emergency calls cannot be handled with usual AT+CHLD commands (e.g.,
> AT+CHLD=11 does not hang up emergency calls)

That is a bit nasty, is there an assumption that every other call is
hung up when an emergency number is dialed?

>   (ofono cannot hangup emergency call and it does not notice when it ends)
> - emergency call gets number "112" and type 128 (unknown type of
> number and numbering plan)

Again, most likely because MBM uses its own voicecall extensions.
Driving it with CLCC is wrong...

> 
> Please find attached log. I first made call to 99999 (an ordinary
> service number within our lab network) then 118 (non-existing service
> number) then 112 (emergency call).
> 
> The emergency call was terminated by callee around 02:58:52 (as you
> can see, modem indicates it with +CIEV=8,0).

These are Bluetooth Handsfree indicators btw, not typically used for
driving a real modem...

Regards,
-Denis