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Update for 16-01-22 16:45

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Tyler Perkins 2022-01-16 16:45:01 -05:00
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tech/GSM.wiki
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@ -3,6 +3,24 @@
GSM or the global system for mobile communications is a standard developed to GSM or the global system for mobile communications is a standard developed to
standardize cellphones and their communication and infrastructure. standardize cellphones and their communication and infrastructure.
GSM handsets derive the baudrate from very very accurate clocks on the base
station.
== Bands ==
GSM occupies
* 850 (USA)
* 900 (europe)
* 1800 (europe)
* 1900 (USA)
*NOTE* GSM-900 uses 880-914mhz
The 33cm ham band is 902-928mhz. Therefore, for 902-914 we can transmit legally
as a eurpean tower.
This band is also the ISM (industrial scientific medical) band. Most devices on
this band are low power and low utilisation.
== IMSI == == IMSI ==
International Mobile Subscriber Identity is a way for devices to id themselves International Mobile Subscriber Identity is a way for devices to id themselves
@ -12,3 +30,6 @@ on a GSM network. An IMSI is a secret key that is stored on the SIM card.
A spoofed GSM tower. In GSM the base station (tower) picks all settings A spoofed GSM tower. In GSM the base station (tower) picks all settings
including Tx power, Rx gain, encryption, etc including Tx power, Rx gain, encryption, etc
When the tower tells the handset to disable encryption (A5/0), and handset
_should_ tell user about this. Hoever every manufacturer disables this