
Ask HN: Sim card control frequency? - ParameterOne
Does the sim card control the frequency transmitted?  And does the transmitter in the phone allow for a large range of frequencies, like from below 900Mhz up to and past wifi (2.4Ghz)??
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jepler
I am not a specialist in GSM networking, but I went looking at the relevant
standards documents to see whether I could answer your question.

It appears that the handset can request information from the SIM about
frequency bands. For example, see section 10.3.38 of 3gpp specification #11.11
"Specification of the Subscriber Identity Module - Mobile Equipment (SIM - ME)
interface", which discusses EF_CPBCCH: "CPBCCH storage may reduce the extent
of a Mobile Station's search of CPBCCH carriers when selecting a cell"
[https://portal.3gpp.org/desktopmodules/Specifications/Specif...](https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=419)
[click 'versions' and then the link '8.14.0' to get a zip of a doc file that
renders like hell in libreoffice 5 on debian stretch]

However, after that I lose myself in random standards document and can't give
a clearer or more authoritative answer.

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sbierwagen
The SIM card doesn't contain the radio, the phone itself contains the radio.
Phones can only transmit on a fairly narrow set of frequencies, you can't tune
one to an arbitrary frequency in the gigahertz range.

If you want to transmit on an arbitrary frequency you'll need to buy a
software defined radio, like the HackRF [http://www.kr4.us/HackRF-
One.html?gclid=CJGdyMDLqtQCFYGUfgod...](http://www.kr4.us/HackRF-
One.html?gclid=CJGdyMDLqtQCFYGUfgodhdkE_A)

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byoung2
It would seem not, since phones (at least in the US) are required to be able
to connect to the tower in the absence of a SIM card for 911 calls.

~~~
ParameterOne
Are 911 calls analog?

