Hi, I have to read from an (virtual) comport to receive the event from a photosensor. There is no protocol, just if something passes through, there is at pin x power (pins 4,6 and 7,8). I've seen the example for the COM Port usage with asio, sofar I've not seen anything to monitor a single/multiple pins. http://www.nabble.com/Simple-serial-port-demonstration-with-boost-asio-async... Also I am not sure, if I need to, would it be enough, to just connect and then perform an async_read on the comport? Actually I don't have to get the data really, as its probably not really "data", all I need to know is when data comes in. Is asio the right library to handle this? Are there other options? regards Jens Weller -- Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger