diff --git a/app.js b/app.js
index aa7ea6fa4..a875710fc 100644
--- a/app.js
+++ b/app.js
@@ -1351,8 +1351,7 @@ $(document).bind('fatalError.jingle',
 function callSipButtonClicked()
 {
     $.prompt('<h2>Enter SIP number</h2>' +
-        '<input id="sipNumber" type="text"' +
-        ' value="' + config.defaultSipNumber + '" autofocus>',
+        '<input id="sipNumber" type="text" value="" autofocus>',
         {
             persistent: false,
             buttons: { "Dial": true, "Cancel": false},
@@ -1366,7 +1365,7 @@ function callSipButtonClicked()
                 if (v)
                 {
                     var numberInput = document.getElementById('sipNumber');
-                    if (numberInput.value)
+                    if (numberInput.value && numberInput.value.length)
                     {
                         connection.rayo.dial(
                             numberInput.value, 'fromnumber', roomName);
diff --git a/config.js b/config.js
index bf086564a..e4ed41b04 100644
--- a/config.js
+++ b/config.js
@@ -16,7 +16,6 @@ var config = {
     minChromeExtVersion: '0.1', // Required version of Chrome extension
     enableRtpStats: true, // Enables RTP stats processing
     openSctp: true, // Toggle to enable/disable SCTP channels
-    //defaultSipNumber: '20669', //Default SIP number used in call dialog
 //    channelLastN: -1, // The default value of the channel attribute last-n.
 //    useRtcpMux: true,
 //    useBundle: true,