[Elecraft] K3 Key Input

[Brett Howard]

Being that I'm not around my rig I'm using the schematic as a reference
after searching the manual and not finding what I need. 

The Key input looks like if its enabled its got +5V on the port that
needs to be able to be sunk to ground.  

Am I reading that right?  Has anyone seen this in another area
documented and/or verified this with a meter?

Thanks much

~Brett

PS:  I'm asking as I'm wondering if I should order the WKUSB kit or go
ahead and spend the WKUSB-HV kit which can switch units that have 3.3V
or less on the key in jacks.  

Thanks much...