[GreenKeys] Speed Converters

[jhhaynes at earthlink.net]

jhhaynes at earthlink dot net


n Wed, 14 Jun 2006, Keith Densmore wrote:

> Hi Y'all
> Back around 1980 ASCII  to baudot (and vica versa) speed converters were common. Some were built into the FSK converter and some were seperate. Does anyone have one of the  seperate units either homebrew or commercial or a construction article about the same.
>
> Thanks,
> Keith, VE3TS
Just recently Jack had a Black Box speed and code converter on sale on 
ebay.

Back in the 70's or so there was a design for a box that used FIFO
integrated circuits so you could run your Model 28 at 100 WPM and
use it in amateur RTTY at 60 WPM.  I often advocate this to people
looking for 60 speed gears for their Model 28s, as it is more
impressive to the public to be able to run the 28 at full speed
100 WPM and then for radio use the speed converter takes care of
things.  Plus the speed converter acts as a regenerative repeater,
and that is advantageous especially in radio reception.

Receiving of course is easy since the printer at 100 WPM stays ahead
of the data stream at 60.  It's for transmission that you need the
FIFO buffer since the keyboard is running faster than the radio can
transmit the characters.  The box I'm thinking of had an analog
meter on it to show you how full the buffer was getting, so you
would not overflow it if you could type that fast.

I guess the modern way to do this would be to use Gil's circuit board
and a microcontroller, rather than FIFO chips.