Robert, as Itamar said: don't use thread -- you likely don't need them in your scenario. shameless self-plug: http://www.youtube.com/watch?v=va7j86thW5M https://github.com/tavendo/AutobahnPython/tree/master/examples/wamp/serial2w... The example includes both Arduino code and Twisted/Autobahn code .. communicating over serial. No locking. Everything async. Maybe thats of use while learning .. /Tobias Von: twisted-python-bounces@twistedmatrix.com [mailto:twisted-python-bounces@twistedmatrix.com] Im Auftrag von Robert Voigtländer Gesendet: Montag, 21. Oktober 2013 13:57 An: Twisted general discussion Betreff: Re: [Twisted-Python] serial communication - getting started Thanks for the fast reply. I don't yet understand your answer. I may have to dig more into Python. On 21 October 2013 13:45, Itamar Turner-Trauring <itamar@itamarst.org<mailto:itamar@itamarst.org>> wrote: On 10/21/2013 07:35 AM, Robert Voigtländer wrote: def SerialInit(): ... reactor.run() thread.start_new_thread(SerialInit()) if __name__ == '__main__': print("-----") s.write('123456789') #s.write("\n") 1. Twisted is not thread-safe, so you can't call methods on the protocol from another thread. 2. As a result, you're probably best off not using threads at all. 3. A reasonable place for the write() might be in your Protocol's connectionMade method. _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com<mailto:Twisted-Python@twistedmatrix.com> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python