Tektronix TDS1000- and TDS2000 102 TDS1000/2000-Series Digital Oscilloscope User Manual, NOTE. To view an Ext, Ext/5, or AC Line trigger signal, push and hold down the TRIG VIEW button.

Reference
102 TDS1000/2000-Series Digital Oscilloscope User Manual
Source Options.
Source option Details
Numbered chan-
nels
Triggers on a channelw hether or not the waveformis
displayed
Ext Does not display the trigger signal; the Ext option uses the
signal connected to the EXT TRIG front-panel BNC and
allows a trigger levelrange of +1.6V to --1.6V
Ext/5 Same as Ext option, but attenuates the signal by a factor of
five, and allows a trigger levelrange of +8V to --8V.; this
extends the trigger level range
AC Line This selectionuses a signal derived from the power line as
the trigger source; trigger couplingis set to DC and the
trigger level to 0 volts
Use when you need to analyze signalsrelated to the
frequency of the power line, such aslighting equipment
and power supply devices;the oscilloscop e automatically
generates the trigger,sets the Trigger Coupling to DC, and
sets the Trigger Levelto zero volts
The AC Line selection isavailable only when you select the
Edge trigger type
NOTE. To view an Ext, Ext/5, or AC Line trigger signal, push and
hold down the TRIG VIEW button.