[Trlog] Strange laptop LPT behavior

[George Fremin III]

On Thu, Mar 13, 2003 at 08:46:41AM -0500, N9CO at aol.com wrote:
> Whenever the LPT port keying/ptt/paddle adapter is connected, the PTT is 
> activated, and alternating Morse dots and dashes (di-dah-di-dah-di-dah...) 
> are sent at whatever speed TR is set to.  It seems that something is shorted 
> in the LPT port on the PC.  This same LPT adapter works fine on my regular 
> DOS PC.  It works fine on my LINUX box, too.
> 


7.1.5 	The paddle interface just sends dits or dit-dah-dit-dah.

	Some computers do not have a pull-up resistor on the parallel port
	inputs. It might be necessary to provide pull-ups to +5 Volts on the
	two inputs used by the paddle. This can be done by connecting a 10K
	resistor from each paddle input to pin 14 on the parallel port
	connector. Pin 14 is held at +5 volts and will pull the inputs up to a
	high logic level when the paddle input is open.



-- 
George Fremin III - K5TR
geoiii at kkn.net
http://www.kkn.net/~k5tr