I assume you may have seen this... for that radio
" Also documented is the PC-Radio interface I have constructed for which I make little or no claim of originality! Radio Set up Quite simply put, the manual that came with the radio in some areas is at best misleading, and in others actually wrong. Lets start with the basics. When the radio is in data mode there are two actual modes available. One is "DATA LSB" where both the DATA and LSB indicators are showing, and the other "DATA USB" where both the DATA and USB indicators are showing. What the manual doesn't tell you is that "DATA LSB" is FSK RTTY only, and "DATA USB" is AFSK RTTY and also suitable for use on all sound card based digital modes. On the back of the radio is an "AFSK-FSK" switch. All this switch does is route pin one of the data port either to the audio circuitry when in "AFSK" or to the tone generator when in "FSK". So, for most of us this switch needs to be in "AFSK" mode and the radio in "DATA USB". The actual sideband that the radio is in is controlled by menu item U-46. For typical RTTY operation, this needs to be set to "2125-L", this sets the carrier injection up for an offset of 2.125 kHz in a pseudo-LSB mode, so that the transceiver actually is operating in LSB mode even though the display still indicates "DATA USB". Conversely setting menu item U-46 to "2125-U" will put the radio in USB mode. It would appear that many digimode operators have experienced problems trying to run the FT-920 in true Data mode. Reports I have seen include "I used the Yaesu Data port on the original design but had to disconnect the data in line and move it to the Yaesu phone patch in jack. I discovered that the data port is only functional in the data mode (not in standard modes like USB and LSB) and the data mode adds information to the data in line, which causes problems." It is worth noting at this point that the audio in via the data port is only active when the radio is in Data mode. However, the use of the data port has a number of advantages over using the mic socket or "phone patch" connections, here are some of the best: 1. The mic socket is not active in data mode, so you don't need to plug the mic back in every time you wish to operate phone and rip it out again when you go back onto digimodes. The mic gain control can be left set for phone use. 2. There is also no risk at all of transmitting in data modes with the speech processor switched on -- go on we've all done it -- it's not active. 3. In DATA mode the Narrow "CW" filter is active when the narrow button is pressed. This is not available in true SSB modes. In QRM type conditions on PSK or RTTY this is very valuable. You tune the signal in, hit the narrow button and then wind the shift control until the signal is loud and clear. What QRM? Radio PC Interface I wanted to build an interface for the Radio to PC that would work on all sound card based digimodes, but it seemed a useful feature to add a keyboard CW facility via the Comm port DTR line with PTT for all modes utilising the RTS line. A search of the web located the following useful site: http://www.qsl.net/wm2u/inter_ft.html >From here there is a link to KC7DS's web site where a suitable interface can be found: http://www.qsl.net/kc7dh/sndcrd.htm