Ted, If you upgrade to a K4 instead of a K3, the connection is easy, just dedicate the K4's independent RS-232 jack to the SteppIR cable.
But this SteppIR cable WILL NOT WORK with the K3S/P3 without a very specific splitter connection, unless you're willing to give up all computer control of your K3 (I assume not). The K3S or K3 + KIO3B has both USB and RS232 jacks, but they are tied together by the CBLP3Y when CONFIG:RS232 is set to USB instead of 38400. The two jacks do not operate independently like the K4's USB and RS-232 jacks. The Serial Box (S-BOX) was designed to make the connection of a SteppIR to a K3S+CBLP3Y+P3 very easy, and you can return your SteppIR cable for a refund because you won't need it. I'll contact you off list with a connection diagram, since this reflector doesn't support attachments. What the S-BOX does is taps into the RXD line (Pin 2) in the CBLP3Y "PC" connector, and splits one side to the SteppIR, with the other side going back into the P3's "PC" connector. So all lines in the CBLP3Y still pass straight through the S-BOX to the P3, but the RXD line is split and passed to the SteppIR controller as well, so it can track the K3's band changes (SteppIR AutoTrack mode). You must not connect the TXD line (Pin 3) in the SteppIR cable to the K3 or P3, otherwise nothing will work. You should also use the Elecraft Key Line Interrupt in series with the KPAK3AUX cable set to open the keying line (Pin 10) in the Elecraft AUX cables, so that the SteppIR controller can open the keying line to the amplifier while it is tuning, to prevent high power from damaging the SteppIR antenna or KPA500. The KAT500 also opens this amp keying line while it is tuning, for the same reason. You will need the following cables for safe (interruptible) keying of your amplifier: K3 ACC -> Elecraft Key Line Interrupt (a DE-9 M/F gender changer with Pin 10 open) -> Elecraft AUX Cable -> KAT500 XCVR KAT500 AMP -> Elecraft AUX Cable or straight 15-pin cable -> KPA500 ACC1 K3 KEY OUT (RCA) -> 3.5mm TRS to Dual RCA Cable -> SteppIR PTT (3.5mm TRS) SteppIR PTT -> 3.5mm TRS to Dual RCA Cable -> KAT500 KEY IN (RCA) KAT500 KEY OUT (RCA) -> KPA500 KEY IN (RCA) I can supply clearly-labeled versions of all of these cables in various lenghts if needed. 73, Bob, N6TV https://bit.ly/S-BOX On Tue, Mar 11, 2025 at 6:10 PM Ted Edwards W3TB <w3tb....@gmail.com> wrote: > I am going to be putting up a SteppIR BigIR vertical soon. > They send me a cable for Elecraft connection in order to deliver the > frequency to the control box. > My question is exactly where to connect the SteppIR control box to the > radio. > > My station: > K3 with the upgraded I/O board KI03B and also the upgraded VFOs like came > in K3S. > Also the P3 Panadaptor with display out board for a monitor. > Also the K-knob, KPA 500 amplifier, and KAT500 tuner. > > Thanks ahead of time for your wisdom on this. > > > -- > 73 de Ted Edwards, W3TB and GØPWW > > and thinking about operating CW: > "Do today what others won't, > so you can do tomorrow what others can't." > ______________________________________________________________ > 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 > Message delivered to n...@arrl.net ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
