[Elecraft] K3 Digital modes

[Greg KA2COP]

I've been toying with the idea of outfitting my KAT-500 with a new K3!  The
KAT-500 being the only Elecraft product I own right now is getting lonely
and needs a "playmate."

All humor aside, my search of this group hasn't found what I'm looking to
find out.  I occasionally use PSK31 but I use JT65 very often, almost
daily.  I'm trying to piece together what I have learned so far regarding
JT65.

It appears the audio part of the digital interface between the K3 and the
computer is fairly straight forward.  The rear panel "mic" and "mono out"
seem to be the logical point to connect to the computers sound card.

As far as keying the transmit or PTT I'm not quite sure how this is
accomplished.  I see there is a KUSB cable to connect the K3 to the
computer with FTDI chipset and drivers.  Can PTT be handled by the USB
cable?

I'm not very interested in options which include using the front microphone
or headphone jacks or placing the mic near the speaker.

Thank you

Greg

KA2COP