On Sun, 29 May 2016, gareth G4SDW GQRP #3339 wrote:

Suddenly it has clicked after setting up the IC728 for Jim - the reason
that some Morse keys had a shorting switch must have been to
provide a continuous key-down position for tuning the TX and ATU!

I seem to recall in the old days that when switching to AM on some rigs,
you had to pull the key out of the jack (so the jack would then short the
point to ground). If so, a shorting switch would be useful too.

Michael