I plugged in my some earphones and the beep alarm sound is ear piercingly loud, even on the low noise setting. Can this be rectified in a firmware update as I do like the idea of a headphone jack but I think you could do some damage to someone's ears at the current volume level?
I think you can adjust the volume under User Options -> Alarm Volume.
You can adjust the volume under: Main Menu > User Option > Alarm Beep Volume > Low
However, this has no bearing on the earphone volume level, only the inbuilt external speaker. When earphones are plugged in the sound is around 10x louder than the 'High' volume sound setting which leaves ringing in my ears. It seems the volume level cannot be adjusted when earphones are plugged in.