How do I know when Amazon Echo is streaming my voice to the Cloud?
When Amazon Echo detects the wake word, when you press the action button on top of the devices, or when you press and hold your remote's microphone button, the light ring around the top of your Amazon Echo turns blue. This shows that Amazon Echo is streaming audio to the Cloud.
When you use the wake word, the audio stream includes a fraction of a second of audio before the wake word, and closes once your question or request has been processed. Within the 'Sounds' settings in the Alexa app you can enable a 'wake up sound.' This is a short audible tone that plays after the wake word is recognised to show that the device is streaming audio.
You can also enable an 'end of request sound' that plays a short audible tone at the end of your request, to show that the connection has closed and the device is no longer streaming audio.