Let me explain a bit more. The KRC2 followed the same thinking as the K2 - we put non-RS232 signals on the DE9 pins. That means that only pins 2 and 3 should see those signals, but not the others. I remember there being a warning in the manual about this, but I don’t find it at this point. We will have to do something about that. We have kicked ourselves many times for using this connector arrangement. As they say, that is water under the bridge.
Unfortunately jumpers W11, W12, W19 and W20 do connect DE9 pins 4 and 9 to the micro, through 10K dividers, meaning that if RS-232 signals are connected, they will only be at half voltage. Thus the microcontroller is at risk. But, lets see if it is actually damaged by setting things up properly. The description on page 24 of the KRC2 manual sets up both connectors for use with Icom band voltages. I would suggest using only one of the DE9s for the Icom signals, and leaving the other set up for computer use. Using the XCVR port for the Icom data, remove W11 and W12 and leave W19 and W20 jumpered. You will then want to have jumpers W9 and W10 inserted to allow the computer to talk to the KRC2 using the PC port. Make absolutely sure you only use a three pin cable for this one (this is more of a warning to others following this thread). If you used the opposite connector for the Icom voltage, the jumper settings become: Icom voltages connected to PC port: Remove WW9, W10, W19, W20, Insert W11, W12 (for Icom data) and W21 and W23 for computer data on the XCVR port. There have not been any updates to the KRC2 firmware since V1.6, so you have the latest. If you would like to use the KRC2 Utility to change the band maps, you will most likely want to have jumpers W7 and W8 removed to use 4800 bps communications. I don’t remember if the utility allows any other data rate, but that is currently the best one to use to communicate with the KRC2 with the utility. You should have the connections correct, with Icom Band Voltage on pin 9 and Reference voltage on pin 4. Let me know how this works for you. 73, Jack, W6FB > On Apr 21, 2020, at 4:17 PM, Rich <[email protected]> wrote: > > Installed Jumpers > > W1,2,3 W11,12, 19,20 > > DB9 from Icom Radio Pin 4= 8v ref, Pin9= Icom Band Voltage Pin1=GND > > Do you mean a straight through cable from PC to KRC2? I am sure I did not > break anything. I only had Pin 2 and 3 set for straight and null. Those > pins should certainly not have 12v on them. I hope > > Rich > > On 4/21/2020 18:58 PM, Jack Brindle wrote: >> Rich; >> >> What are the jumper settings in the KRC2? >> >> It is _very_ important not to use a straight-through cable with the KRC2. As >> documented in the KRC2 manual, the pins are connected to the >> microcontroller, and the +/- 12 V excursions of the RS-232 levels will >> damage the microcontroller I/O pins. >> >> There are two voltages you need from the Icom, the band Voltage, and the >> reference voltage. The band voltage output from some Icom radios have been >> shown to drift during transmit, so much that they may show a completely >> different band. For this reason the band reference voltage (+8V) needs to be >> used. It is this voltage that drifts, and thus the Band voltage follows. >> >> With that in mind, the W9 - W22 jumper settings are important and will >> connect/disconnec the various pins to the DE9 connectors from the >> microcontroller. >> >> 73! >> Jack, W6FB >> >> >>> On Apr 21, 2020, at 3:11 PM, Rich <[email protected]> wrote: >>> >>> Does anyone have any experience using the KRC2 with an Icom radio? This is >>> a working KRC2 that was on a K3 at one time. >>> >>> To start I cannot get the KRC2 to connect to my PC. I have used straight >>> through cable, Null modem Cable and a USB to Serial Cable. I have run the >>> program on an old XP laptop and my Win10 machine. I have even used a >>> "real" comport. None of those configurations will connect to the device. >>> The DL switch is set properly. >>> >>> The KRC2 passes all of the manual button press tests. >>> >>> I have the jumpers set for ICOM on KRC2 board. The ICOM is sending the >>> band voltage to the unit as measured with a Volt meter. >>> >>> Do you really need the computer to make it work? I am thinking that is >>> mainly for firmware and antenna relay settings >>> >>> I am just trying to control a 419B bandpass filter. >>> >>> Any thoughts? >>> >>> Rich >>> >>> K3RWN >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
