Keypad

Backlit screens were not common in 1990.

But when it's backlit, it's color and when it's frontlit, it's black and white at three times the resolution.

And in this impossibly beautiful picture, you see the main rings backlit by the Sun, you see the refracted image of the Sun and you see this ring created, in fact, by the exhalations of Enceladus.

Some data loggers interface with a personal computer and utilize software to activate the data logger and view and analyze the collected data, while others have a local interface device (keypad, LCD) and can be used as a stand alone device.