Dear J, LF Group,
See the attached circuit. The up/down output pulse widths are roughly 100ms,
which I guess should be OK - if you want to change that, scale the values of
the two 10uF time constant capacitors. The supply voltage isn't critical;
5 - 15V certainly is OK. The RS232 voltage levels can vary over a similar
range.
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: J. Allen <[email protected]>
To: LF (RSGB) <[email protected]>; <[email protected]>
Sent: Sunday, July 16, 2006 7:01 AM
Subject: LF: DFCW on TS450
> All,
>
> Tests here show the UP an DN pins on the TS450 front Microphone connector
do
> move the frequency up and down when in transmit on CW.
>
> The QRS software shift signal from the computer is intended to key a
single
> line to ground to switch mark frequency from shift.
>
> Does anyone have a circuit for 74XX series ICs to switch the signals from
> that line to close the circuit momentarily on either the UP or DN pins?
>
> I am working on it with a breadboard and am tired right now and it is not
> happening for me.
>
> J
> VY1JA
>
>
>
>
DFCWupdn.gif
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