diff --git a/relay.py b/relay.py
index 93119f9..ce617c0 100755
--- a/relay.py
+++ b/relay.py
@@ -74,7 +74,7 @@ if action != 'status':
     bytes = ser.readline() 
     #print ('Renvoie :\r\n' + bytes) 
 
-ser.write('?RLY\r\n')
+ser.write('?RLY\r\n'.encode('ascii'))
 answer = ser.readline()
 status = ''
 for char in answer: