Video Trig Slope: select Positive to trigger on a rising edge, or Negative to trigger on a falling edge.
External 1 Trig Slope: select Positive to trigger on a rising edge, or Negative to trigger on a falling edge, and enter a Level in Volts.
External 2 Trig Slope: select Positive to trigger on a rising edge, or Negative to trigger on a falling edge, and enter a Level in Volts.