When you call the tower or ground for the first time at a controlled aerodrome, you must immediately tell them which ATIS information you have heard. This is done by stating the identification letter at the very beginning of your initial contact.

The format is:

For example:

"Zurich Tower, HB-JXR, Information Delta, request vectors to the hold."

Or before departure:

"Vienna Ground, OE-LAB, Information Bravo, request engine start from parking."

This simple transmission tells the controller that you are aware of the current weather, runway in use, and any restrictions. The controller knows you are current and does not need to repeat this information to you.