TomTom VIA Reference Manual page 20

A grey bar means your voice is too quiet for the device to recognise individual words.

For some phrases, your VIA repeats what you say and asks for confirmation.
Tip: For the best recognition of what you say, speak normally without trying to articulate
words in an unnatural way. If there is excessive road noise, for example, you may need to
speak in the direction of the microphone.
3. If the command is correct, say "Yes."
If the command is incorrect, say "No" and repeat the command after you hear the prompt and
tone again.
Your VIA plans a route from your current location to your destination.
Tip: To stop your VIA from listening out for further commands, say "Cancel". To go back one
step, say "Back".
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