diff --git a/asterisk_click2dial/asterisk_click2dial.py b/asterisk_click2dial/asterisk_click2dial.py
index a2084ec..226a7b5 100644
--- a/asterisk_click2dial/asterisk_click2dial.py
+++ b/asterisk_click2dial/asterisk_click2dial.py
@@ -236,7 +236,7 @@ class asterisk_server(osv.osv):
             sock.send('Exten: '+str(ast_number)+'\r\n')
             sock.send('Context: '+str(ast_server.context)+'\r\n')
             if not ast_server.alert_info and user.asterisk_chan_type == 'SIP':
-                sock.send('Variable: SIPAddHeader=Alert_Info: '+str(ast_server.alert_info)+'\r\n')
+                sock.send('Variable: SIPAddHeader=Alert-Info: '+str(ast_server.alert_info)+'\r\n')
             sock.send('Priority: '+str(ast_server.extension_priority)+'\r\n\r\n')
             sock.send('Action: Logoff\r\n\r\n')
             sock.close()