[Elecraft] K3: Use of KX3 USB/RS232 cable

[Edward R Cole]

I have been trying to use the KX3 USB/RS232 cable to command my K3 
via its RS232 port.  I assumed that this would  require only the RXD 
and TXD connections that is supported by the KX3 cable.  But it will 
not establish contact with the K3.

I have a conversion box with a stereo 3.5mm mini-phone connector 
connected to a DB9 for making the connection with the K3.  Tip 
<-->pin-2 (DB9) and Ring <--> pin-3 (DB9);  Gnd <--> pin-5 (DB9).

My K3 Prolific USB/RS232 cable makes contact with the K3 with no issues.

The KX3 cable is connected via com-3 while the K3 cable is connected 
via com-5.  Looking at these ports on the device manager the 
appropriate drivers are installed for each port and indicate they are 
working.  Com-3 connects to the KX3 fine and com-5 connects with the 
K3 fine (using the appropriate utility sw).

Just wondering if there is something incompatible between these two 
serial cables that they cannot be used with the other radio?

The reason for asking is that I need both com ports to support 
operation from two programs that need to communicate simultaneously 
with the K3.  One sw is only requires RTS or DTR to control PTT, 
while the other sw is using RXD and TXD to execute a frequency command.

Both programs operate correctly with the K3 if I use the K3 serial 
cable to connect them.

73, Ed - KL7UW