It uses GSM, which can be listened to by a RTL-SDR or any other software defined radio.
http://www.rtl-sdr.com/receiving-decoding-decrypting-gsm-sig...
It uses GSM, which can be listened to by a RTL-SDR or any other software defined radio.
http://www.rtl-sdr.com/receiving-decoding-decrypting-gsm-sig...