Cannot read again when no barcode was scan before



I'm developing an application for handheld barcode scanner Motorla MC32NO (Android 4.1) using Symbol EMDK for Android v 3.1. I used codes from basic and advanced scanning tutorials just to be sure I'm doing nothing wrong. Now I have a problem with trigger. If I pull the trigger, laser turns on and I can read barcodes.  But if I pull it without scanning any barcode, laser turns of and I cannot scan any more barcodes until I restart my activity.
When I pull the trigger and hold it, scanner status is SCANNING and after a while it changes to IDLE, then the laser turns off and onData event is not fired of course. If I then release and pull the trigger again nothing happens.
I also tried to simulate this behavior with DWDemo application which was shipped with my barcode scanner. It turns the laser on again regarding I scanned barcode or not. I attached my source code. Can you please tell me how can I force my app to behave to turn the reader on everytime I pull the trigger?
Thank you