Phil, Do you have the KXIO2 option in your KX2? If so, that is where the plug for that option is. 73, Don W3FPR On 12/18/2018 6:34 PM, Phil Hystad via Elecraft wrote: > On the KX2 end-cap, near the power adapter, is an arrow pointing around the corner I presume with the label AUX. What is this for? Can’t find any mention in the KX2 user guide. >