How to go directly to the next line after validating a value in a page.

I need to go directly to next line in a page who contains only 2 fields which the first one will get his value by scanning a barcode.
The problem that i got is when i scan a barcode, $ is automaticly inserted to the next field in the page.
So i want to keep scanning barcodes whithout pressing enter to go to the nextline.

Anyone can help me ?

Thanks