switch position turns on all LCD segments.
switch position displays the software version
number.
switch position displays the model number.
Disables beeper. (bEEP)
Enables "Smoothing" mode. (S---)
Dampens display fluctuations of rapidly changing
inputs by digital filtering.
(YELLOW)
Disables automatic power-down ("Sleep mode").
(PoFF)
Sleep mode is also disabled while the Meter is in a
MIN MAX AVG Recording mode, or the AutoHOLD
mode.
Disables automatic 2-minute backlight timeout.
(LoFF) (Model 177 and 179 Only)