Openmoko IMEI survey

Mychaela Falconia mychaela.falconia at
Sat Aug 19 02:43:06 UTC 2017

Ben Deering wrote:

> The US GTA02 I still have (FCC EUNGTA02) uses 3546510116xxxxx.

Thank you for the info!  Thanks to this tidbit from you, we know now
that FIC was quite lax in (not) following the official IMEI rules,
using the same TAC (the first 8 digits of the IMEI) for devices with
different frequency band hardware configs, which is a no-no per the
official rules...

I am still waiting for confirmation on that one, but it also appears
that they used the same TAC for both GTA01 and GTA02, contrary to the
official rule that the TAC must be different for every new model no
matter how minor the change is.  (The *only* difference they allow to
exist within one TAC is the case color!)  The entry for TAC 35465101
in GSMA's IMEI database lists the manufacturer as "FIC" (not Openmoko)
and the model as "FIC Neo1973 Smartphone", so all evidence suggests
that it was originally obtained for GTA01 and later reused for GTA02.
The same IMEI database entry also lists the frequency bands as
"GSM 1800,GSM 1900,GSM 900", so clearly the reuse of the same TAC for
the "US" GTA02 version was a later hack.

My own opinion: while I do not particularly agree with reusing the
same device type code (TAC) for devices with different frequency bands
in the hardware, I fully applaud FIC (or was it OM after they split
off?) for breaking the absolutely idiotic rule about getting a new TAC
for every change in the hardware model, no matter how invisible and
irrelevant a change like GTA01->GTA02 is from the perspective of GSM
networks.  Seeing FIC (or OM) take the TAC that was officially
assigned for GTA01 devices only and reuse it for the GTA02 will
certainly help me justify further reusing the same TAC for my GTA02-
derived FCDEV3B modems. :-)

> I have not tried inserting a SIM, but I have heard that frequencies
> have been repurposed and that it probably wouldn't work in the US and
> more.

I live in USA-occupied Incalia (one of the ancient names for the
continent now called North America), specifically on land which USA
wrongfully and forcibly took from Mexico (California), and I use
nothing but GSM/2G cellular devices.  Furthermore, none of these
GSM/2G devices that I use even have that "US" 850 MHz band, instead
they are all "European triband" or what I call tri900 in FreeCalypso,
i.e., 900/1800/1900 MHz, and they make use of the GSM/2G services in
the 1900 MHz PCS band.  The operator is T-Mobile USA.

The FCDEV3B modem board I have built is a clone of the tri900 ("EU")
version of the GTA02 in RF hardware terms.  I would not know how to
build a tri850 version unless someone tells me what SAW filter part
number I should populate for the 850 MHz band in the place of the
B7820 for the 900 MHz band.  I am hoping to never need to build
Om-style tri850 hardware and to go directly to quadband instead
(following TI's Leonardo+ and E-Sample designs) for my next hardware


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