[Elecraft] N6XI NAQP RTTY July, 2007 with K3

[Jeff Stai]

Lyle Johnson wrote:
>> From my perspective, those keying circuits want to be inside the 
>> radio, safe from harm. Is there any reason why they weren't made part 
>> of the radio - or why I shouldn't put them in when I get my K3? 
>> (Assuming of course I can get into that part to do so...)
> 
> The K3 accepts open collector(or open drain) to ground as inputs, or can 
> be driven with 0 <= x <= +5 volts.
> 
> Some stations use RS232 levels (which can be as high as +/- 25V) for 
> direct FSK.  Such levels need to be converted to 5 volts for the K3 
> digital inputs.  Further, RS232 specifies a "1" as -3 < x < -25V and a 
> "0" as +3 < x < +25V, so a polarity inversion (in hardware or software) 
> is also required.
> 

hi Lyle - I appreciate that - but I believe that in 2007 the chances are pretty darn good that those 
inputs will be driven by a station computer, and that serial port is pretty well known - kind of 
like the serial port for controlling the radio, right? I'm just saying this was an opportunity to 
put the level shift in the radio, and I wonder why it wasn't, and why I couldn't/shouldn't modify my 
own K3? thanks! - jeff wk6i

-- 
Jeff Stai               jds at twistedoak.com
Twisted Oak Winery      http://www.twistedoak.com/
Winery Blog             http://www.elbloggotorcido.com/