Heartway Medical Products S12S User Manual page 16

Operation Features
(1) Switch High / Low speed by pressing button! once. (TRN as control signals) Press
one time: High-speed <<--->> Low-speed
(2) Take exterior turn-switch as determinant signal (TRN as control signals).
Symbols on LCD
＂H＂symbol means "High Speed"
＂L＂symbol means "Low Speed"：
Flicker Frequency 1 sec
! 16