Figure 29. LED Configuration
The MS9540 has three LED indicators located on the head of the scanner.
The MS9520 has two LED indicators located on the head of the scanner.
When the scanner is in operation, the flashing, or stationary activity of the LEDs
indicates the status of the scanner and the current scan.
All LEDs are Off
The LEDs will not be illuminated if the scanner is not receiving power from the
host or transformer.
The scanner is in stand-by mode, and CodeGate is enabled. Present a bar
code to the scanner and the green LED will turn on when the laser turns on.
Steady Yellow (MS9540’s Only)
The CodeGate button is not active. If a bar code is in the scan field, the laser
will turn on. The bar code will be decoded and transmitted to the host
When the laser is active, the green LED is illuminated. The green* LED will
remain illuminated until the laser is deactivated (default mode only).
Steady Green and Single Red Flash
When the scanner successfully reads a bar code, the red* LED will flash and
the scanner will beep once. If the red LED does not flash or the scanner does
not beep once, then the bar code has not been successfully read (default mode
After a successful scan, the scanner transmits the data to the host
device. Some communication modes require that the host inform the
scanner when data is ready to be received. If the host is not ready to
accept the information, the scanner’s red LED will remain on until the
data can be transmitted.
* In some custom units the standard green LED has been replaced with a blue LED and
the red LED has been replaced with a white LED.