Sony Ericsson K200i: R1AA003 vs R1AA008

[Vadim Yanitskiy]

Hi Mychaela,

On 01.12.2023 23:01, Mychaela Falconia wrote:
>> Of course the MS Classmark does not contain any bits related to the
>> codec support.  I meant to say the Bearer Capability, but wrote this
>> instead.  In any case, for the sake of completeness, I will compare both
>> the Bearer Capability and the Classmark between those firmware versions
>> and post my findings here soon.

I did some tests in my own Osmocom based network and found out that both 
R1AA003 and R1AA008 look identical on the radio interface, and more 
specifically both phones do indicate both AMR FR and AMR HR as supported.

You can find the Classmark and the Bearer Capability bits in my small 
classmark collection, which I just uploaded here:

https://people.osmocom.org/fixeria/classmark/
https://people.osmocom.org/fixeria/classmark/se_k200_R1AA003.txt
https://people.osmocom.org/fixeria/classmark/se_k200_R1AA008.txt

> I find it very intriguing that a phone manuf created a hidden service
> menu command that (presumably) enables or disables AMR inclusion in
> the advertised speech version list.  I would find it very interesting
> if you could check with your test network to see if that hidden service
> menu setting really does what I just assumed.  As to possible reasons
> why they thought about artificially disabling AMR, please refer to the
> Calypso presentation I just did on OsmoDevCall: AMR support in plain
> Calypso (as opposed to LoCosto or*possibly*  Calypso+) is crippled in
> that it can't do DTXu - hence you have to choose between DTXu (battery
> saving) and AMR (potentially better call quality under poor radio
> conditions) with all Calypso phones...

You can enter this menu yourself by entering the following sequence:

-> * <- <- * <- *

("->" is right, "<-" is left)

This service menu cannot be used to enable or disable specific speech 
codecs.  It has the following hierarchy:

* Service info
** Model info
** Software info
** Configuration <--
** SIM lock
* Service settings
** Contrast
* Service tests
** ...
* Text labels

and "Configuration" is the sub-menu in which I found the AMR state. 
Somehow it does not agree with the Bearer Capability sent by R1AA003.

-- 
Best regards,
Vadim.