diff --git a/src/Message.js b/src/Message.js
index 05d395853..391cdd4b7 100644
--- a/src/Message.js
+++ b/src/Message.js
@@ -18,8 +18,8 @@ JsSIP.Message = function(ua) {
 JsSIP.Message.prototype = new JsSIP.EventEmitter();
 
 
-JsSIP.Message.prototype.send = function(target, body, contentType, options) {
-  var request_sender, event, eventHandlers, extraHeaders,
+JsSIP.Message.prototype.send = function(target, body, options) {
+  var request_sender, event, contentType, eventHandlers, extraHeaders,
     events = [
       'sending',
       'succeeded',
@@ -34,6 +34,7 @@ JsSIP.Message.prototype.send = function(target, body, contentType, options) {
   options = options || {};
   extraHeaders = options.extraHeaders || [];
   eventHandlers = options.eventHandlers || {};
+  contentType = options.contentType || 'text/plain';
 
   // Set event handlers
   for (event in eventHandlers) {
@@ -54,7 +55,7 @@ JsSIP.Message.prototype.send = function(target, body, contentType, options) {
   this.closed = false;
   this.ua.applicants[this] = this;
 
-  extraHeaders.push('Content-Type: '+ (contentType ? contentType : 'text/plain'));
+  extraHeaders.push('Content-Type: '+ contentType);
 
   this.request = new JsSIP.OutgoingRequest(JsSIP.C.MESSAGE, target, this.ua, null, extraHeaders);
 
diff --git a/src/Registrator.js b/src/Registrator.js
index c7c3f275b..f26ae7db6 100644
--- a/src/Registrator.js
+++ b/src/Registrator.js
@@ -47,11 +47,15 @@ JsSIP.Registrator = function(ua, transport) {
 };
 
 JsSIP.Registrator.prototype = {
-  register: function(extraHeaders) {
-    var request_sender, cause,
+  /**
+   * @param {Object} [options]
+   */
+  register: function(options) {
+    var request_sender, cause, extraHeaders,
       self = this;
 
-    extraHeaders = extraHeaders || [];
+    options = options || {};
+    extraHeaders = options.extraHeaders || [];
     extraHeaders.push('Contact: '+ this.contact + ';expires=' + this.expires);
     extraHeaders.push('Allow: '+ JsSIP.Utils.getAllowedMethods(this.ua));
 
@@ -164,26 +168,25 @@ JsSIP.Registrator.prototype = {
   },
 
   /**
-  * @param {Boolean} [all=false]
+  * @param {Object} [options]
   */
-  unregister: function(all, extraHeaders) {
-    /* Parameters:
-    *
-    * - all: If true, then perform a "unregister all" action ("Contact: *");
-    */
+  unregister: function(options) {
+    var extraHeaders;
+
     if(!this.registered) {
       console.log(JsSIP.C.LOG_REGISTRATOR +"Already unregistered");
       return;
     }
 
-    extraHeaders = extraHeaders || [];
+    options = options || {};
+    extraHeaders = options.extraHeaders || [];
 
     this.registered = false;
 
     // Clear the registration timer.
     window.clearTimeout(this.registrationTimer);
 
-    if(all) {
+    if(options.all) {
       extraHeaders.push('Contact: *');
       extraHeaders.push('Expires: 0');
 
diff --git a/src/Session.js b/src/Session.js
index ef94bd02d..96e5679c8 100644
--- a/src/Session.js
+++ b/src/Session.js
@@ -72,7 +72,7 @@ JsSIP.Session.prototype.init_incoming = function(request) {
   this.receiveInitialRequest(this.ua, request);
 };
 
-JsSIP.Session.prototype.connect = function(target, options) {
+JsSIP.Session.prototype.connect = function(target, views, options) {
   var event, eventHandlers, request, selfView, remoteView, mediaType, extraHeaders, requestParams;
 
   // Check UA Status
@@ -89,10 +89,16 @@ JsSIP.Session.prototype.connect = function(target, options) {
     throw new JsSIP.Exceptions.InvalidStateError();
   }
 
+  // Check views
+  if (!views || (views &&  !views.remoteView)) {
+    console.log(JsSIP.C.LOG_INVITE_SESSION +'Missing "views" or "views.remoteView"');
+    throw new JsSIP.Exceptions.InvalidValueError();
+  }
+
   // Get call options
   options = options || {};
-  selfView = options.views ? options.views.selfView : null;
-  remoteView = options.views ? options.views.remoteView : null;
+  selfView = views.selfView || null;
+  remoteView = views.remoteView || null;
   mediaType = options.mediaType || {audio: true, video: true};
   extraHeaders = options.extraHeaders || [];
   eventHandlers = options.eventHandlers || {};
diff --git a/src/UA.js b/src/UA.js
index 8326bb3d7..328b85622 100644
--- a/src/UA.js
+++ b/src/UA.js
@@ -68,10 +68,10 @@ JsSIP.UA.prototype = new JsSIP.EventEmitter();
  *
  * @throws {JsSIP.Exceptions.NotReadyError} If JsSIP.UA is not ready (see JsSIP.UA.status, JsSIP.UA.error parameters).
  */
-JsSIP.UA.prototype.register = function(extraHeaders) {
+JsSIP.UA.prototype.register = function(options) {
   if(this.status === JsSIP.C.UA_STATUS_READY) {
     this.configuration.register = true;
-    this.registrator.register(extraHeaders);
+    this.registrator.register(options);
   } else {
       throw new JsSIP.Exceptions.NotReadyError();
   }
@@ -83,10 +83,10 @@ JsSIP.UA.prototype.register = function(extraHeaders) {
  *
  * @throws {JsSIP.Exceptions.NotReadyError} If JsSIP.UA is not ready (see JsSIP.UA.status, JsSIP.UA.error parameters).
  */
-JsSIP.UA.prototype.unregister = function(all, extraHeaders) {
+JsSIP.UA.prototype.unregister = function(options) {
   if(this.status === JsSIP.C.UA_STATUS_READY) {
     this.configuration.register = false;
-    this.registrator.unregister(all, extraHeaders);
+    this.registrator.unregister(options);
   } else {
     throw new JsSIP.Exceptions.NotReadyError();
   }
@@ -130,18 +130,11 @@ JsSIP.UA.prototype.isConnected = function() {
  * @throws {JsSIP.Exceptions.InvalidTargetError} If the calling target is invalid.
  *
  */
-JsSIP.UA.prototype.call = function(target, useAudio, useVideo, eventHandlers, videoViews) {
-  var session, options;
-
-  // Call Options
-  options = {
-    views: videoViews,
-    mediaType: {audio: useAudio, video: useVideo},
-    eventHandlers: eventHandlers
-  };
+JsSIP.UA.prototype.call = function(target, views, options) {
+  var session;
 
   session = new JsSIP.Session(this);
-  session.connect(target, options);
+  session.connect(target, views, options);
 };
 
 /**
@@ -155,16 +148,11 @@ JsSIP.UA.prototype.call = function(target, useAudio, useVideo, eventHandlers, vi
  * @throws {JsSIP.Exceptions.InvalidTargetError} If the calling target is invalid.
  *
  */
-JsSIP.UA.prototype.sendMessage = function(target, body, contentType, eventHandlers) {
-  var message, options;
-
-  // Message Options
-  options = {
-    eventHandlers: eventHandlers
-  };
+JsSIP.UA.prototype.sendMessage = function(target, body, options) {
+  var message;
 
   message = new JsSIP.Message(this);
-  message.send(target, body, contentType, options);
+  message.send(target, body, options);
 };
 
 /**