Fluke 281 User Manual page 217

SYNC OUT is turned on and off by alternate presses of the output soft-key.
The selection of the signal to be output from the SYNC OUT socket is made using the
src (source) soft-key; repeated presses of src cycle the selection through all the
choices (waveform sync, position marker, etc.) listed above. Alternatively,
with the src selected (double-headed arrow) the rotary control or cursor keys can be
used to step backwards and forwards through the choices.
The source selection of the SYNC OUT waveform can be made automatic (auto) or
user-defined (manual) with alternate presses of the mode soft-key. In automatic
mode the SYNC OUT waveform most appropriate for the current main waveform is
selected.
For example, waveform sync is automatically selected for all continuous standard
and arbitrary waveforms, but trigger is selected in trigger or gated waveform
modes. The automatic selection will be mentioned in each of the appropriate main
waveform mode sections and a full table is given in the appendix.
The automatic selection can still be changed manually by the src soft-key even when
auto mode has been selected but the selection will immediately revert to the automatic
choice as soon as any relevant parameter (for example, main waveform frequency or
amplitude) is adjusted. You must select manual with the mode soft-key for a source
other than the automatic choice to remain set. The auto selection will generally set
the most frequently used signal, for example waveform sync for all continuous
main waveforms, but you will need to use manual for any special requirements, such
as position markers on arbitrary waveforms.
SYNC OUT
output: on
mode: auto
src: waveform sync
Standard Waveforms
Synchronization Output
5
5-7