The main challenge is to improve the response time of linux. It is Not a real time kernel.
The best way is to memory map the gpio for fast polling. That means running it at super user privilige.
The K16 EXT Keyer Kit which I have Is a very in-depth manual for a simple device. Also it brings back the concept of transmitter on / off timing as Steve has built in the functions of transmitter timing as part of the keyer and has separate outputs for the Transmitter PTT and the transmitter keying circuits. This is something that was very common with the older tube transmitters (my old Johnson Valiant, and HQ-170 Receiver) the good old days all 83 pounds of transmitter, just what you want for a POTA Hi Hi and do not forget just throw that in your back pack and go SOTA, S-U-R-E -!!!
