[TRLog] LPT port queston

[George Fremin III - K5TR]

On Tue, Apr 04, 2000 at 11:37:00AM -0700, w2fca@qsl.net wrote:

> According to the manual, you can use one LPT port for CW paddle
> input or radio switching output but not both. It would seem to
> me that this is because there is not always voltage on pin 14
> for pullup.
> My question is - can you get around this if you have another
> source of + 5 volts for pullup on pins 12 & 13?

Yes - you are correct.  You also may not need the pull up 
voltage on all LPT ports but if you change computers you 
may want to build it in anyway so that it will not 
have problems later.  Like when you swap out comptuers 
in the middle of a contest.

Here is the switchbox I built and use.

http://www.kkn.net/~k5tr/trlog/switch.pdf

-- 

George Fremin III        "When a true genius appears in the world,
Johnson City, TX           you may know him by this sign; that the 
K5TR (ex.WB5VZL)            dunces are all in confederacy against him."    
830/868-2510                                   -- Jonathan Swift
geoiii@kkn.net                              
http://www.kkn.net/~k5tr                   

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