What does the Transmission Encryption Key (TEK) do during radio transmissions?

The Transmission Encryption Key (TEK) is crucial for maintaining the security and privacy of communications during radio transmissions. It specifically encrypts and decrypts the operator's voice, ensuring that the information exchanged is not easily intercepted or understood by unauthorized parties. This encryption process protects sensitive data and upholds the integrity of communications, particularly in military or secure environments where confidentiality is paramount.

In contrast, the other options do not accurately describe the function of the TEK. Frequency changes pertain to how the radio signals are transmitted rather than their security. Synchronization is important for ensuring that multiple radios can communicate effectively, but it is managed by different mechanisms, not the TEK. A net identifier relates to identifying the network for communication purposes, which is separate from the encryption of the voice data.