Datamax ST-3210 Operator's Manual page 28

Dual-Purpose Buttons
Depending upon the printer's mode, the buttons function as follows:
On-Line Mode Button Functions
(On-Line, as denoted by the On-Line Indicator being 'On')
PAUSE:
Press this to temporarily stop printing (pause mode) or to
enter the off-line mode.
Press this button in pause mode to resume printing from the
point stopped; or, if in off-line mode press to return to the
on-line mode.
FEED:
Press this button to advance the ticket stock to the next print
position.
TEST:
This button is inactive in the on-line mode.
20 S-Class