diff --git a/pyobd b/pyobd

index 9852fac..e015105 100755

--- a/pyobd

+++ b/pyobd

@@ -594,7 +594,7 @@ the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  0211

         available = []

         for i in range(256):

           try: #scan standart ttyS*

-            s = serial.Serial(i)

+            s = serial.Serial("/dev/ttyS"+str(i))

             available.append(s.portstr)

             s.close()   # explicit close 'cause of delayed GC in java

           except serial.SerialException: