The circuit is a simple one! Just one transistor, a 2N4400 or
equivalent. Basically, you make up a cable with a male db25
connector on one end and a 2 conductor key plug on the other end.
Transistor connections to the male db25 connector end:
The emitter goes to pin 1.
The base goes to a 1K resistor (in series) and then on to pin 17.
Pin 18 goes to the ground side of the cable going to the key plug.
The collector goes to the center conductor of the cable (going to
positive side of the key plug...that goes to the key jack on the
Just plug the male db25 connector into your printer port (lpt1)
and the other into the key jack on your Omni VI. I use Log-EQF
for logging and it is programmed to use this cable to send
cw by pressing alt-K. Also, the NA contest program uses this
cable for pc cw contesting.
73 John K7FD
From: Paul Meier <wa7mig@Hevanet.com>
To: email@example.com <firstname.lastname@example.org>
Date: Thursday, November 05, 1998 5:05 PM
Subject: Re: [TenTec] 301 Advice
>Could you send me or tell me where to find the keying circuit you talk
>about? I've missed that somewhere and can you provide more info on the key
>circuit going to lpt1 and where on the Omni. Key jack I guess! Thanks for
>your help, I've been looking for a keying circuit or a schematic for one of
>the adapter cables.
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