New Cellular/Cellphones is/are digital & encrypted.
CDMA
UMTS
2G 3G
GSM
For example GSM :
The voice is first digitized using a vocoder and a GSM-codec
then it is encrypted using a special encryption-protocol
that protocol is called A5/1 A5/2 ...etc
After that it is put in 1 of 8 timeslots (TDMA)
after that it is transmitted on a RF-carrier.
hhhuuuhuuuh ...........not finished yet : )
....after that the RF-carrier could be
"frequency-hopping" but this is not everywhere implemented
It depends on the network-operator if and wich crypto is used,
worlwide there are just a few countries without it...
Here's a Yahoo-group wich discusses:
http://groups.yahoo.com/group/gsm-scanner
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GSM-scanners , GSM-interception , GSM-monitoring
GSM-detectors , GSM-encryption , GSM-jammers
GSM-cryptophones , GSM-bugs , GSM-spyphones
GSM-Security , IMSI-catcher , SMS-tricks
GSM-tracking+locating , SIM-Cloning , Bluetooth-tricks
Cellphones , WiFi-phones , CDMA , iDEN , DCS , UMTS , DECT
Satphones , Iridium , Thuraya , Globalstar , Teledesic , Inmarsat
Sales or advertising of illegal equipment is not allowed !
We don't allow or encourage any unlawful behaviour !
This group is moderated wich means that it may take a while
before your postings appear.
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There's a few lists about if and where encryption on GSM is used
and how to find that out using your own phone (monitor-mode)
....etc...etc.