I want to say the 970 doesn't transmit a tone. I ran into an issue with my Kenwood D710, if you set the squelch to tone squelch, it will not break open no matter how strong the signal is without the tone. IIRC, the 970 was one of the repeaters I had issues with and forced me to go back and change all the settings. So the 970 is probably 100hz, nothing out.
Ok, with echolink, it can work two ways. Both ways, you download the software and install it on your PC. From there you'll have to verify your call sign with them. After that you can either use a mic and speakers, or a headset directly with the computer, or if you own a kenwood that supports echolink connect the radio directly to the computer via the kenwood cables they sell and use it. It brings up a board that has different node numbers that go all over the world. You can listen into hurricane nets, all sorts of stuff. I haven't really played with it much, but I believe you can talk user to user, or in a chat room setup( I think), or user to repeater. The CRA repeater in Boulder is listed in echolink, so if I logged onto it, you would likely hear it announce my callsign. Then you would just talk to me like I was on a radio in the area.