[Community] Phone with modem monitor

Dr. H. Nikolaus Schaller hns at goldelico.com
Tue Jan 13 22:16:59 CET 2015

Am 13.01.2015 um 22:04 schrieb wonderphone at posteo.de:

> Hi Nikolaus,
> Just an idea: Would it be possible to build a phone that - down from a certain communication layer - logs all the packets that go into the modem from the GSM network? The log would have to be separate from the rest of the phone e.g. on flash memory.

Unfortunately no. Because there is no interface to access these packets. Remember, they are coming over radio frequencies, i.e. are modulated bursts and are decoded in a black box called “3G module” until PCM voice or USB data is coming out of it.

What you are trying is to inspect a data stream inside that black box and the designers of these modules have done everything to make access impossible for us.

> This would not prevent any danger but could be used for analysis of possible attacks or to be sure everything was fine.

Well, such devices exist - but are several kg of weight and big - and very very expensive. They are called GSM protocol tester.

just my 2cts,

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