[1000mp] RTTY using FSK in Mark V Field

[Vermilyea, John]

Dear Group,

I am planning to operate RTTY using FSK with a computer and sound card
and would like to know the best way to generate FSK and control the PTT
using the computer's COM port. The program that I will be using, MMTTY,
just has two open collector NPN transistors to generate the Mark and
Space and PTT signals. The manual just shows using a TNC.Has anyone used
this program before and how did they control the transmitter?
John K3YS