Notes

A note is a feedback component that informs the user about the current situation. A note contains a text and possibly a graphical element. The softkey labels are typically empty because notes do not require user input, although the user can dismiss most notes by pressing any key.

Confirmation	Informs user about a successfully completed operation. Short duration, subtle tone (should not be used after every successful action; see guidelines below).
Information	Provides information about an unexpected situation during usage of the device. Longer duration and more noticeable tone than Confirmation note. Errors that are not too serious should result in an Information note.
Warning	Used when the user must be notified about something that may require action. Fairly long duration, and sound can be heard (and distinguished) even when user is not concentrating on the phone, for example, battery-low warning.
Error	Warning to the user. Should only be used when the user has tried to do something that may cause a substantial problem.
Permanent	A note that must remain on the screen for an indefinite time. User cannot dismiss it, for example, Insert SIM card notification.
Wait and progress	A note containing wait or progress graphic (wait graphic is an animation of indefinite duration; progress graphic is an expanding bar used to indicate duration of an operation). Used for long operations. When possible, user should be able to stop the operation. For this purpose, a softkey, for example, Cancel, is provided.

The following guidelines about these note dialogs' usage helps you decide when to use what note.

Use a Confirmation note when:

The effect of an operation cannot be seen directly by some other means, for example, Added to Album, when the album view is not currently visible.
There is relevant information to be communicated, for example, Last Call Duration.

However, designers should consider whether a Discreet pop-up could be used instead, because a Confirmation note interrupts the user’s task flow, while a Discreet pop-up does not.

Confirmation notes should not be used after every completed operation, as it may annoy users.

Confirmation notes should not be used when:

There is already another dialog in the procedure, for example: Do you want to remove this message? Y/N.
A progress indication is visible during the procedure.
The user can see the result of the operation when it is performed, for example, when adding or removing objects in a list.
A setting has been changed. The new value of the setting is visible in the setting item.
The operation is minor, or happens so frequently that a note would be annoying, for example, Copy-Paste actions.

Use an Error note when the user does something that may cause considerable harm immediately or later, for example, providing the wrong PIN code. Repeating this action a couple of times would block the SIM card.

To keep Error notes effective, they should be used very sparingly. In most ordinary error cases, an Information note should be used instead, because it has a less aggressive sound and graphics.

Note: If the information is something the user must see and acknowledge, a Confirmation query is better than a note. In such cases, the user must press a key to dismiss the information, and there will be time for him/her to read and think about the notification.