[Elecraft] ptt-key

[Keith Trinity WE6R]

PTT KEY setting not Sticky upon reboot power cycle. See Manual ERRATA;
https://ftp.elecraft.com/K3S/Manuals%20Downloads/E740258E%20K3S%20Owner's%20man%20errata%20A1-2.pdf
PTT/KEY USE WITH THE USB PORT IMPROVED: Some PC applications can control 
PTT and KEY at the K3S via the RTS/DTR signals of the USB port. However, 
use of these signals may also allow the PC’s USB port initialization to 
unexpectedly activate transmit at the K3S. 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
Keith WE6R K3/K4 Tech