Re: AT!ICCID before PIN-entry fails

[Andrew Bird <ajb spheresystems co uk>]

> On Thursday 18 July 2013 11:54:51 Andreas Schigold wrote:
>
> Andrew Bird , 16.07.2013 10:45:
>
>
>
> Hi Andreas,
> Have you tried reading the files directly from the SIM using AT+CRSM ? I
> believe the SIM should have the ICC file available before unlock, probably
> for the exact reason you need it, so it may circumvent the vendor's
> firmware logic that prevents you from reading with AT!ICCID
>
> Hope it helps,
> Andrew
>
> Hi Andrew and Aleksander,
>
> thanks for your help. An extra command "AT+CPIN?" could not change the
> situation. After powering the modem it has enough time to initialize all,
> especially if I use a terminal-tool to talk with the modem not by
> application but by keyboard. :-)
>
> The CRSM-command delivers a somehow encoded ICCID, right? So It would help
> to prevent a false try. AT+CRSM=176,12258,0,0,10
> AT+CRSM=176,12258,0,0,10
> +CRSM: 144,0,"98942000008036496082"
>
> OK
>
> But there is the other use case to show the ICCID the user when he enters
> the PIN (in a web-gui at a LAN-port). So he can prevent a mistake if he
> prepares many devices in the office before shipping them to their
> installation places. Then I need the decoding algorithm. Do anyone know a
> paper where it is described?
>
> For the moment this here is my solution: In the current version of the
> firmware Sierra supports the undocumented format of the command:
>
> AT+ICCID
> instead of
> AT!ICCID?
>
> a plus instead of exclamation mark and without the question mark:
>
> --> AT+ICCID
> <-- AT+ICCID
> <-- ICCID: 89490200000863940628
> <--
> <-- OK
>
> This works fine. But to prepare the case that future firmwares won't support
> this variant I'm very interested on the decoding algorithm. It seems that
> each pair of digits is exchanged. Is this it? Or is this a coincidence? And
> what about an ICCID with 19 digits?
>
> Thanks and greetings,
>
> Andreas Schigold
Hi Andreas,
   To be honest I can't remember what the encoding is called, but it is as you 
say pair swapped. If the length is odd it's padded with the 'F' character. I'm 
pretty sure it's used elsewhere in mobile comms, so ModemManager may have an 
implementation already, but I'm a Wader guy so I don't know.

Andrew