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Re: [SD-User] serial cw keying cable

Subject: Re: [SD-User] serial cw keying cable
From: Paul Whatton <>
Date: Sun, 14 Jan 2007 11:41:48 +0000
List-post: <>
Coincidentally Bob I set up SD to key my rig (IC746) for the first time 
yesterday. I too tried to use an existing cable and had exactly the same 
problem as you, tune worked but the rig did not key. The problem was the 
pin out on the serial connector. The PTT line (RTS) from the serial port 
was connected to the key input on the rig not the key line (DTR).

I solved it in about ten minutes by making up a new cable just as Paul 
suggests in the SD instructions on page 10.

The DTR line on the serial port is used for keying so, assuming you have 
a modern rig and not one with HV keying line, you'll need to drive the 
base of any old small NPN transistor through about a 2k2 resistor from 
DTR which, on a 9 pin D connector is pin 4. Ground is pin 5. Then the 
rig is keyed across collector/emitter.

It works fine now. The keying is perfectly useable and with a bit of 
adjustment to the weighting doesn't sound bad at all. But I do have a 
few of those Windoze timing issues and get occasional changes in speed. 
Plus of course my paddles and the computer are not speed locked 
together. So I've just ordered Winkey.

73 Paul G4DCV

Bob Elsinger wrote:
> I'm not having any luck with cw keying using the serial port. It is the same 
> cable I use with CT by K1EA. I can key the rig using the tune command but no 
> cw is happening. I don't think it's the cable. I wonder if any of you have 
> had similar situations? Thanks in advance
> Bob Ve6ux
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