Ok, here's what worked for me. Maybe it will help out someone else. I already have the Radio Shack stereo to mono adapter. It went into the line out jack on my computer( or the headphone jack of cassette player, CD, etc..) I used the same 6' mono cord I use to hook up the caller. Plugged it into the mic jack on the DVR. That's all there is to the connection.
I have also been recording in HQ mode, it sounds better to me. Not sure about 'yotes though.
Here's where I think I had a breakthrough. I was originally recording about 30 seconds of silence in front of and after each sequence. It started out ok, but the hiss increased as silence went on, until it was unacceptable. I did some reading in the owners manual ( when all else fails read the directions) and learned this unit has a built in automatic recording level control that adjusts mic sensitivity for optimum recordings. I think since it couldn't hear anything to record it was upping the sensitivity level and that's where I got the hiss.
I have since recorded only a second or two of silence and the recordings have come out excellent.
Hope this helps and wasn't too long.
John