In this video I show how to capture GSM traffic over the air, and decrypt parts of our own voice call. As frequency hopping is enabled in our case, a "test call" is decrypted subsequently, to show the full process until I get my new SDR, and record a new video.

Please note that the pace in this video is quite fast at times, to keep the time on the video down a bit.

It's also highly recommended to check out the previous videos, in case this is the first time you're doing GSM sniffing and decryption.

Generally speaking, decoding voice where frequency/channel hopping is disabled/off, is almost the same as decrypting SMS's. The only difference is an extra step at the end, where the TCH/F channel is used for speech data.

New topics covered in this video:
- Voice calls decryption (Traffic channels (TCH/F), channel hopping, etc.)
- RTL-SDR limitations in relation to frequency hopping
- Decrypting the test call file by "Security Research Labs"

Topics already covered in the SMS decryption video:
- Switching USB…