Hello, This page has many important hints and kinks to set up, or troubleshoot problems you might come across while being a new digital interface user.
On your computer, you need at least a 16 bit audio card, which would be at least a Soundblaster Pro or better. Even though you will be using ONLY Left Channel Audio, the other channel might be needed for additional applications. Learn to adjust audio levels , usually by trial and error, and when you have the correct settings for certain modes, you will want to save them for recall in a wonderful freeware named Quickmix. More on this later.
To get your feet wet in this, start out with PSK31, and the easiest, and best software that I have found is Hamscope. Looking through this software, you will want to pay attention in the setup to how the serial line is set for keying the rig from within the software. On the Donner Interfaces, and interfaces from some of the other manufacturers, is to use the RTS lines to key the rig. If you later want to "hard key" CW from the keyboard, those units utilize the DTR lines.
Make sure that you have the audio cables plugged into the proper jacks on the computer, ie: Cable with RED Marker connects to the "Line Out", or Speaker out of the soundcard, and the Cable with NO Marker connects to the "Line In", or the "Mic" in port of the soundcard. These connections are what you will use on most softwares used for digital modes.
Next, If you have NO Serial Port on your computer, you will need to purchase a USB to Serial Adapter. It should come with drivers, which MUST be installed. If they are not installed, you will have one of the following: Rig Keyed all the time, or Rig will not key when transmit is clicked. Again, set the software to key via RTS!
Now then, if you have a power setting on your radio, set the power to NO MORE THAN 20 watts. More than that will make for a wide and dirty signal, not to mention run the finals out of the radio, as digital modes are a "Key Down" situation. Make sure that you have a good SWR, which is also important. Next, on a popular PSK31 frequency, tune around to see a Yellow Line or Lines going down the screen of your monitor..... these are stations in operation. Click on one of the lines, and you should see the QSO in progress on your monitor.
Next, find a clear spot on the waterfall, and key the software, either to call a CQ, or to do a quick test. You will want to set the soundcard up to where you achieve just about the power that you set the rig to.... that will be the "Line Out" or "Speaker Out" slider that you will adjust to get the 20 watts. You are then ready to get your feet wet in the digital modes. With both the receive and transmit audios set properly, it is a good idea to save the settings for recall in a GREAT Freeware named "Quickmix". Some sound settings may vary a bit from mode to mode, so to save lots of re-setting, grab that software.
Note: On Rigs that have no power level setting, you can adjust the audio levels going into the audio in circuit of the rig, until you reach the 20 watts, which is just about the same as above.
And.... if your audio for receive is set too high, you will have way too much "Yellow Snow" on the waterfall to find weaker stations calling a CQ, or calling you.