FC UI firmware: battery management and MMI codes

[Das Signal]

Hi Mychaela,

> If there is no official demarcation, i.e., if it is not possible to
> define MMI codes that are guaranteed to never conflict with anyone's
> USSD codes, then I reason that the only available course of action is
> to make our MMI codes long enough to reduce the chance of collision -
> thus ###xxx# seems better in this regard than #xx# or #xxx#.  Right
> now I am thinking of defining the following MMI codes for FC:
> 
> ###240#: bring up battery and charging status screen
> ###241#: start charging user request
> ###242#: stop charging user request
> ###364#: shorter alternative to *36446337464# for Eng Mode menu
> ###520#: display firmware version

I'm not sure about what is supposed to be the norm in general, apart from
classic codes (eg *#06# for IMEI) it seems many OEM just make up stuff.
Android has the particularity of their secrets codes usually beginning
with *#*# and ending with #*#* such as *#*#4636#*#* but not all OEMs
follow this route, eg. Samsung's baseband info uses *#0011#. I'm personally
fine with ###{number}# as it's easier to type and I don't think it would
clash with an existing USSD. This page shows a number of predefined USSD
codes: https://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data as well as
https://www.etsi.org/deliver/etsi_ts/122000_122099/122030/10.00.00_60/ts_122030v100000p.pdf
and I don't see any that start with ### :-)

--DS