HP 54710A User's Reference Manual page 281

Trigger Menu
This chapter describes the trigger menu, and explains how you can
use its controls to trigger the oscilloscope. The trigger circuit
performs two functions. It locates the waveform of interest, and it
synchronizes the oscilloscope measurement and display to the
waveform.
The trigger menu that is displayed when you enter the trigger menu
depends on the selected trigger mode. The menu for each trigger
mode is included with the discussion of that mode. Edge is the
default trigger mode.
18–2