[WT-support] PTT keying

[Stewart GM4AFF]

Thanks for all the replies. Maybe it's me, but the diagrams on page 181/2 of
the manual show a COM port or parallel port CW keying arrangement - not PTT.
I've made these interfaces before. Neither of these show how you would
interface the port with the radio's PTT. Does pin 16 on the LPT port or pin
7 of the COM go high or low when 'keyed'? How much current could these pins
sink? Not much - not a relay? So could the circuits be extended with another
1k resistor and another transistor from the appropriate pins? These would
close the PTT from LPT pin 16 or COM pin 7? Apologies for the persistence,
but I'm not an electronics engineer and it still isn't clear to me.
Thanks!
Stewart


-----Original Message-----
From: support-bounces at win-test.com [mailto:support-bounces at win-test.com]On
Behalf Of Stewart GM4AFF
Sent: 09 November 2007 20:26
To: support at win-test.com
Subject: [WT-support] PTT keying


Apologies if this has been asked before. Is there a circuit for and an
explanation of the PTT functionality built into WinTest for use with COM and
LPT ports? Ideally I would like a little circuit not just for keying the
(LPT pin 17) CW (as in the Wiki) but also showing how the rig PTT could be
closed by (LPT) pin 16. Also interested in how this functionality is adapted
to cope with laptops which only have USB ports (which adapters work, which
don't, etc).

Many thanks,

Stewart
GM4AFF



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