The start pulse isn't missing, otherwise there'd be no printing. What the machine interprets as a start bit is the first bit that opens the loop. I think the difference in the two presentations in the link is mostly due to the 555 RY gen sending a 1-bit-length stop bit but the radio RYs are using something longer (1.5 bit length stop bit or even 2.0).

Wayne
WB4OGM

On Saturday, December 30, 2023 at 12:39:07 PM MST, B. Smith <[email protected]> wrote:


Since the Start pulse is missing when using the "RY Generator" the
machine does react a little differently. See
http://k4che.com/Tempvideo/RY%20Comparison/555RYComp.mp4
k4che

On 12/29/2023 6:10 PM, [email protected] wrote:
> A start pulse is the same length as any of the data bits. A stop is
> usually about 1.5 bits length but machines will work with stops of
> just one bit length. The only unique aspect of a start or stop bit is
> when they occur.
>
> On Friday, December 29, 2023 at 03:21:00 PM MST, Gene Smar via
> Milsurplus <[email protected]> wrote:
>
>
> Breck:
>
> I'm not a RAT aficionado so my question is out of ignorance as well as
> curiosity. Doesn't something have to generate start and stop pulses
> for a TTY machine to print something? Thanks.
>
> 73 es HNY de
> Gene Smar AD3F
>
>
> Sent from my Radio Shack TRS-80 model 100 laptop
>
>    On Fri, Dec 29, 2023 at 1:35 PM, B. Smith
>    <[email protected]> wrote:
>    For you teletype fans I've posted info on the RY Generator.
>    K4CHE
>    http://k4che.com/RY%20Generator/RY%20Generator.htm
>
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