[Kenwood] Magicom Board for TS-820 What?

[Les Zwiebel WB6ORZ]

    Help please: we have a TS-820 here with this board added to the IF board. A Google search has yielded some info, but still need the original instructions that came with this and/or any further info list members can offer here.
   How does this thing work? How is it switched on or off? What does the schematic look like? Does it change the method of adjusting the processor? Is it a compressor or a clipper? What we've read sounds favorable, but I'm bewildered.
    Thanks in advance!
    (((73)))
    Les