Using a barcode Scanner via USB OTG on Samsung Tab S I have a 10 Galaxy Tab S (Android 5.0.2) on which I am connecting a barcode scanner via USB OTG. 

The problem is it does not read the barcodes (Line,2-D, QR ) accurately.  It missed out on some characters.

I have tried the same scanner with the same codes on a computer, a MI Phone &amp; a Samsung Note -II Phone &amp; it works there correctly.

Any Ideas ?
Most USB Barcode scanner guns also have a set of special barcodes you can print and then scan with the gun to set the baud rate (and other settings) of the scanner.  I would try changing that and see if the gun starts working right on that device.

From your message that it's the QD2400, the user manual is full of QR codes you can scan to change the settings of your scanner.  I suspect you just need to change the baud (as stated above), which is on page 30 of your user manual.

The user manual can be downloaded from this URL:
http://www.datalogic.com/eng/products/automatic-data-capture/general-duty-handheld-scanners/quickscan-i-qd2400-pd-612.html

The name of the PDF where I saw the QR codes for all the setting changes is:
820055914.pdf