Edit in JSFiddle

$(document).ready(function () {
    
    var keyupFiredCount = 0; 

    function DelayExecution(f, delay) {
        var timer = null; 
        return function () {
            var context = this, args = arguments;
           
            clearTimeout(timer);
            timer = window.setTimeout(function () {
                f.apply(context, args);
            },
            delay || 300);
        };
    }
    $.fn.ConvertToBarcodeTextbox = function () {

        $(this).focus(function () { $(this).select();$("#msg").html(""); });

         $(this).keydown(function (event) {
            var keycode = (event.keyCode ? event.keyCode : event.which); 
            
            if ($(this).val() == '') {
                keyupFiredCount = 0; 
            }  
            if (keycode == 13) {//enter key 
                    $(".nextcontrol").focus();
                    return false;
                    event.stopPropagation(); 
            } 
        });

        $(this).keyup(DelayExecution(function (event) {
            var keycode = (event.keyCode ? event.keyCode : event.which);  
                keyupFiredCount = keyupFiredCount + 1;  
        }));

         $(this).blur(function (event) { 
             if ($(this).val() == '')
                 return false;

             if(keyupFiredCount <= 1)
             {
                 $("#msg").html("<span style='color:green'>Its Scanner!</span>");
                 //alert('Its Scanner'); 
             }
             else 
             {
                 $("#msg").html("<span style='color:red'>Its Manually Typed!</span>");
                 //alert('Its Manual Entry');
             }

             keyupFiredCount = 0;
         }); 
    };
    try {
        $(".barcodeinput").ConvertToBarcodeTextbox();
        if ($(".barcodeinput").val() == '')
            $(".barcodeinput").focus();
        else
            $(".nextcontrol").focus(); 
    } catch (e) { }

});

Enter/Scan Barcode : <input type="text" id="txtCode" class="barcodeinput"/>
<input type="button" value="OK" class="nextcontrol"/>
<h3 id="msg"/>