[RTTY] Intel NUC, anyone?

[Joe Subich, W4TV]

 > So my next question is, how to the commercial USB interfaces that
 > support FSK actually do it?  Are they skipping the RS-232 part and
 > just wiggling (at 45.45 bauds) some wire that connects to the radio's
 > FSK port?

The microHAM "keyer" interfaces (not USB Interface II and III) contain
a microprocesor with a UART.  The UART is used for FSK with the baud
clock programmed for the required baud rate.  microHAM goes so far as
to alias 45 baud (Windows can set only integer baud rates) to 45.45
baud so the timing is exact.  Further, with MK II, DK II, MK2R and
micro2R, the processor will insert a diddle character if there is no
data in the FIFO to prevent a "long" stop bit.

I can't answer for other manufacturers but as far as I know all of
them are using "dumb" USB to serial converters or, in some cases,
USB to parallel devices with with shift registers to clock the bits
at a specific rate.

73,

    ... Joe, W4TV


On 10/26/2017 3:05 PM, Peter Laws wrote:
> On Thu, Oct 26, 2017 at 4:20 AM, David G3YYD <g3yyd at btinternet.com> wrote:
>> Using EXTFSK(64) or for that matter 2Tone FSK using bit diddling of a COM
>> port control line is one way of making sure you get extra errors on the far
>> ends decode and being asked to repeat.
> 
> No RS-232 headers, either, in a NUC, which I was secretly hoping for.
> 
> I did also look at the jitter info Oba-san has on his site referring
> to EXTFSK64.  So USB -> RS-232 -> FSK radio port isn't the best way to
> do this (even though it's done all the time).
> 
> So my next question is, how to the commercial USB interfaces that
> support FSK actually do it?  Are they skipping the RS-232 part and
> just wiggling (at 45.45 bauds) some wire that connects to the radio's
> FSK port?
> 
> 
>