Here is a great way to save some cash if you need an FSK interface.

We found this at  http://www.w1hkj.com/FldigiHelp-3.21/PseudoFSK.html .I couldn't find an inexpensive small box I liked, so I used the pill bottle.

This interface dose the same thing the expensive store bought ones do. You take the audio tone from your right audio channel of your computer, running say FLDIGI

http://www.w1hkj.com/ and rectify it and turn the base of a simple NPN transistor on and off giving your shift pin on your RTTY jack on your rig a change in state, so open to ground.

That's it, nothing more no magic. It takes a few hours to build and works great. I used tantalum capacitors and 2% resistors to keep the tolerance stable over time.

All the parts can be bought at Mouser Electronics http://www.mouser.com/?cm_mmc=google-_-ppc-_-americas-_-Brand&gclid=CNWHl-aOiK4CFdQAQAodZVBC6g

Do not cheep out on the transformer and use something used, buy a new one for $5.00 part number TY-304P, I built two for $25...

If you build one send us a picture and will post it. 

73's K9XD