There are various ways for a computer to key a rig. (1) From the computer's parallel port, using a transistor/resistor combination to translate parallel-port levels to typical +5 volt straight-keying line level. The cable runs from the parallel port to the rig's straight-key jack.
(2) From the computer's serial port, using a similar transistor/resistor combination, again to the straight-key input jack. This is NR4C's situation. (3) In the case of the K3 only, from the computer's serial port to the K3's RS232 input, using a straight-through cable just like the one used for firmware updates. In case (1) or (2), if the rig uses one jack for both straight-key and paddle input, that jack must be set for straight keying when the computer is plugged into it. This is the situation when I computer-key my K1. If the rig has separate jacks for straight key and paddle, or if your computer program provides for it, the paddle can be used simultaneously with the computer program to key the rig. This is convenient when the computer gets snarled during a contest. In case (3), the K3 CONFIG menu must be set to key via the serial cable, as Don Wilhelm noted. I computer-key my K3 this way. Methods (1) and (2) work with any rig, although you might need an adapter if the rig uses grid-block or cathode keying, where the voltages/currents are out of the range of the little transistor/resistor combination. For example, I computer-key my Heathkit SB-401 (about 20 volts negative) using (1) and an optoisolator IC. As far as I know, method (3) is unique to the K3. But I'm not familiar with the no-front-panel software-defined rigs, so maybe they have similar inputs. 73, Paul W8TM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
