diff --git a/lib/kiss/kiss_serial.rb b/lib/kiss/kiss_serial.rb
index b3d91ba255923c58cc3f58bb9408cc8c24af84dd..e14957b20d1a45f89a5655f01c0a782304ade05d 100644
--- a/lib/kiss/kiss_serial.rb
+++ b/lib/kiss/kiss_serial.rb
@@ -30,7 +30,11 @@ module Kiss
         protected
         def read_interface
             read_data = @serial.read(@read_bytes)
-            read_data.map { |c| c.ord }
+            if read_data
+                return read_data.map { |c| c.ord }
+            else
+                return nil
+            end
         end
 
         protected