Question: What happens to commands sent to the Terminal Adapter (TA) after an audio data stream has started using the `+VTX` action command?
Option 1: They are ignored until the data stream is terminated.
Option 2: They are processed immediately, pausing the audio data stream.
Option 3: They are embedded in the audio data stream and shielded using `<DLE>` methods.
Option 4: They trigger an error response from the TA due to conflicting operations.
Explanation: This is correct because, according to the specification, once the audio data stream has started with the `+VTX` command, any subsequent commands to the Terminal Adapter (TA) must be embedded within the data stream itself. The use of `<DLE>` (Data Link Escape) methods is a standard technique for shielding or distinguishing these embedded commands from the regular audio data, ensuring both can coexist in the same stream without confusion. This approach allows for seamless management of the transmission process without interrupting the audio data flow.