diff --git a/src/SmscRuChannel.php b/src/SmscRuChannel.php
index dcfd14f..a7bd3b7 100644
--- a/src/SmscRuChannel.php
+++ b/src/SmscRuChannel.php
@@ -75,6 +75,14 @@ protected function sendMessage($recipients, SmscRuMessage $message)
             $params['time'] = '0'.$message->sendAt->getTimestamp();
         }
 
+        if ($message->call) {
+            $params['call'] = $message->call ? 1 : 0;
+        }
+
+        if ($message->voice) {
+            $params['voice'] = $message->voice;
+        }
+
         return $this->smsc->send($params);
     }
 }
diff --git a/src/SmscRuMessage.php b/src/SmscRuMessage.php
index a0c6153..8c98e9d 100644
--- a/src/SmscRuMessage.php
+++ b/src/SmscRuMessage.php
@@ -25,6 +25,28 @@ class SmscRuMessage
      */
     public $sendAt;
 
+    /**
+     * Sign of a voice message.
+     * When forming a voice message, you can transfer both text and attach files.
+     * Files added to the message must be transferred using the POST method in the body of the http request.
+     * 0 (default) is a regular message.
+     * 1 - voice message.
+     *
+     * @var bool
+     */
+    public $call;
+
+    /**
+     * Voice used to read text (for voice messages only).
+     * m (default) - male voice.
+     * m2 is a male alternative voice.
+     * w is a female voice.
+     * w2 is a female alternative voice.
+     *
+     * @var string
+     */
+    public $voice;
+
     /**
      * Create a new message instance.
      *
@@ -86,4 +108,32 @@ public function sendAt(\DateTimeInterface $sendAt = null)
 
         return $this;
     }
+
+    /**
+     * Set the sign of a voice message.
+     *
+     * @param  bool|null  $call
+     *
+     * @return $this
+     */
+    public function call($call = null)
+    {
+        $this->call = filter_var($call, FILTER_VALIDATE_BOOLEAN);
+
+        return $this;
+    }
+
+    /**
+     * Set the voice used to read text (for voice messages only).
+     *
+     * @param  string  $call
+     *
+     * @return $this
+     */
+    public function voice($voice = null)
+    {
+        $this->voice = $voice;
+
+        return $this;
+    }
 }