After you've got everything running and set up, the Inward Connections Mix 690 Summing Mixer will take care of itself. The parameters on the front of the unit simply control panning for each of the 16 available channels. There is also a stereo pair of VU metering, and an overall output level parameter. This isn't the type of gear that you will be constantly playing with, as it does its job after being set up, with only the panning parameters to work with. I haven't seen a manual of this, so I can't say anything about it's make up.
The difference between having the Inward Connections Mix 690 Summing Mixer and not having it in a digital Pro Tools HD based system is incredible. If you are worried about having too thin of mixing coming from the digital realm, this will cure any sort of worrying. It adds fullness and clarity to your sound, making it more realistic and true to its original source. Like I said earlier, you can't get varying tones from this or anything like that, as this is simply a summing mixer which stays in place, but the difference between having it and not having it is pretty unreal.
If you're looking for a fuller, warmer sound for your home or professional studio, and don't have a console, the Inward Connections Mix 690 Summing Mixer can replace this need. While pretty expensive, when compared to having a whole console it doesn't seem like much. Everything from what you hear during mixing to the actual end mixes themselves will sound better when ran through the Mix 690. I'd recommend it to any user with a digital set up that is looking to cap the harshness of a digital signal a bit...