Cleaning The Reading Window - Panasonic CF-20 Series Operating Instructions And Reference Manual

Hold the reader farther away when reading a larger barcode, and closer in when reading a smaller barcode.
Perform reading so that the entire symbol falls within the center of the red Barcode Reader light.
The reader can still read a barcode even if the barcode is not in the center of the red Barcode Reader light.
However, if a part of the barcode lies outside the Barcode Reader light, the barcode cannot be read. Make sure the entire barcode is
inside the Barcode Reader light.
Correct

Cleaning the Reading Window

If the reading window is dirty, gently wipe the reading window with a cloth or a cotton swab moistened with water.
Do not allow materials that can easily scratch the reading window to touch the window, such as sandpaper or metal object.
For parts other than the reading window, see
Decode Capabilities
Following symbologies are supported as the factory default.
Codabar, Code 128, EAN 128, Code 39, DataMatrix, Interleaved 2 of 5, PDF417, QR Code, RSS-14, RSS Limited, RSS Expanded, UPC-A,
UPC-E, EAN-8, EAN-13
Following symbologies also can be used by specifying them with Barcode Configuration Utility.
Codablock A, Codablock F, Code 11, Code 128 French CIP, EAN 128 Irregular, ISBT, Code 93, EAN.UCC Composite CC-A/B, EAN.UCC
Composite CC-C, EAN.UCC Composite Linear, ISBN, ISMN, ISSN, Matrix, Maxicode, MicroPDF417, MSI, Plessey, Standard 2 of 5, Telepen,
UPC-E1, TLC 39, Australian Post, BPO, Dutch Post, Japan Post, Planet, Postnet, Canada Post, Infomail, Sweden Post
Barcode Reader Light
"Handling and Maintenance".
Incorrect
Barcode Reader Light