Hi, George. I use three DB9 ABCD switches in my SO2R station. Let's call them "Left", "Right" and "Development computer". I write software for the K3 and I very frequently need to send firmware from my development computer to one of my two K3s.
Each of two K3s is connected to the "common" center connector of the corresponding "Left" and "Right" DB9 ABCD switches. The "A" input of the Left and Right DB9 ABCD switches is connected to MK2R+ cables. The "B" input of the left and right DB9 ABCD switches goes to "A" and "B" of the "Development computer" switch. The center of the "Development computer" switch goes thru a KUSB USB to Serial adapter to my development computer. To operate with the MK2R+, I switch both Left and Right DB9 switches to "A". To load firmware, I switch both Left and Right DB9 switches to "B". I switch the "Development computer" DB9 switch to A to load the left K3 with firmware, and "B" to load the right K3 with firmware. I've had no difficulties with two of these boxes in series. I use a one meter DB9 "straight through" jumper from Left and Right DB9 switches to the back panel of my K3s. I use another one meter jumper from the Left and Right DB9 switches to the "Development Computer" DB9 switch. I use a two meter or sometimes two two-meter jumpers from the development computer to the "Development computer" DB9 switch. Whew! A picture would be easier, I think. 73 de Dick, K6KR -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, December 17, 2010 7:45 PM To: [email protected]; [email protected] Subject: [Elecraft] Use of DB9 Switch with K3? At times, my microHam CW Keyer is connected to my K3 via the P3. However, when I want to download new firmware for the K3, I have to disconnect the CW Keyer from the RS232 port, and connect the DB9 from the computer's serial port to the K3 via the P3. Can I use a DB9 A/B switch to switch between the the two DB9 cables without creating any problems? 73, George George Wagner, K5KG Sarasota, FL 941-400-1960 cell ______________________________________________________________ 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 ______________________________________________________________ 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

