Your 'Zahlteller' is commonly referred to as a transfer tray, or pass-through tray. The fact that it is 'herausdrehbar' could possibly mean that it is a swivel tray, either swivelling on the horizontal axis (see first web ref) or on the vertical access, where the customer places money or card on his side of the window, whilst the agent places the ticket or wares on the other side, and at the flick of a switch, the tray swivels and the two are exchanged.