[Elecraft] K3 FSK mode Newbie question

[Patrick Skerrett]

Trying to build an interface for FSK mode on my K3 for use with MMTTY.

When I put the rig into data mode & then select the "DATA MD" button and 
spin the sub VFO, I see the option for "FSK  D" mode.

Great, however it also comes up as "USB " and "REV". For me to decode in 
this mode I have to set MMTTY to "Rev" mode.

I thought that FSK mode would be LSB. However, I cannot figure out how 
to change "FSK  D" to use LSB.

Am I just totally confused?

Thanks.

W9PDS