[Elecraft] [K3S] Radio transmits when computer powered on

[Lyle Johnson]

In cases like this, please check the firmware release notes for the 
radio.  The info is often not found in the manual, which gets updated 
infrequently.  I added the bolding...

73,

Lyle KK7P

*MCU 5.33 / DSP 2.86 / FPF 1.23, 8-3-2015*
...

** PTT/KEY USE WITH THE USB PORT IMPROVED:*  PC applications can 
activate PTT and KEY at the K3S via the USB port's RTS/DTR signals. 
However, initial setup of the rig's USB port by the PC may cause pulsed 
or continuous activation of the transmitter. This can happen if the 
computer is turned on after the K3S, or if the USB cable is not 
connected. There is now a "Safe" mode (the default) which disables 
PTT-KEY transmit until the K3S receives a command via USB, such as a 
read of the rig's VFO frequency. *To turn on safe mode on/off, go into 
CONFIG:PTT-KEY and tap '1' to select "USB SAFE" or "UNSAFE". Exit the 
menu and turn the K3S off/on. *Applications that use PTT-KEY via USB but 
never send commands may require "UNSAFE" mode. In this case, unwanted 
transmit can be avoided by turning the PC on before the K3S.


> I've lost track of the (menu?) setting that prevents the K3 or K3S from
> going into TX when the attached computer is powered on.