Some Commodore CBM and Sharp MZ-80B keyboards (U.S. version) feature an RVS key, which is linked to an LED on some keyboards (similar to Caps Lock). German CBM keyboards seem to feature a Control key instead of RVS.

What was the RVS key good for? All I know is that on systems without RVS, Ctrl+R was used to toggle RVS on and off.

  • It is purely historic usage. Tied to the BASIC interpreters that were commonly used in those old computers.
    – Tonny
    Commented May 18 at 23:15

1 Answer 1


REV == Reverse.

As far as I can remember it swapped foreground and background colors for text.
You had to type Shift-Reverse to undo that setting.

Note that it didn't inverted the whole display. Just the characters typed while the setting was in effect.

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