Adtec digital RD-30 (version 2.1.1) Manual - Manual (Page 11)

Controls
Using the Enter, Back and directional buttons (up, down, left, right), the user can control the unit via the front panel.
Control Function
Enter Button Will enter menus and confirm selections.
Back Will back out of menus and escape from item entries.
Up, Down, Left,
Right Arrows are used for menu navigation and for editing configuration
fields within the unit.
10.29.14- v2.1.1