From: jamie_ka1lpa@charter.net   
      
   In article <1446b259-0ae4-4d2d-bf55-677f9128454b@googlegroups.com>,   
   terrypingm@gmail.com says...   
   >   
   > Any suggestions on a no-brainer and safe way to get external input   
   recognised by a PC please? Apart from a voice command approach. Or a solenoid   
   to tap a key. For example a cheap commercial or easily built switch or   
   momentary button with a USB plug at    
   its end. That sort of thing.   
   >   
   > Terry, East Grinstead, UK   
      
   with windows you can use a USB to Serial (RS232) adapter...   
      
   The OS see's most of these on the market as standard so there should be   
   a driver already on board..   
      
    Windows provides a ESCAPE function that allows you to Read and Write   
   the INPUTS and output pins of the port.   
      
    Also Windows provides a WAIT function so that your code can responed to   
   it via a trigger, but this should be done in a secondary Thread or you   
   could simply scan the port at timely intervals.   
      
   you get more input than you do output though..   
      
   For example:   
      
    CD  :Carrier detect;   
    RD  :Ring Detect;   
    DSR :Data Set Ready;   
    CTS :Clear to Send;   
      
    Whereas for output you don't get as much.   
      
    DTR :Data Terminal ready.   
    CTR :Clear to Receive;   
      
   And some devices will support the BREAK single which places the TX pin   
   to low or high state depending on how you do it.   
      
   Depending on how good your adapter is, you can most likely drive them up   
   to around 10Volts without issues but the output will most likely be like   
   around 5 volts, some will actually do 10-12 volts depending on how good   
   they are.   
      
    Hope that helps you.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)