diff --git a/docs/mainframe-design.md b/docs/mainframe-design.md
index 83db717..694d806 100644
--- a/docs/mainframe-design.md
+++ b/docs/mainframe-design.md
@@ -50,7 +50,7 @@ Only one input or output device can be accessed at a time.
 
 1. Use `DEV xx` to select output device _xx_
 2. Use `OUT yy` to write one byte from memory at address _yy_
-3. Use `FED xx` to...
+3. Use `NXT xx` to...
   - card punch: load a new card
   - printer: begin a new line (CR, LF)
   - display: begin a new line