I went to check on our DR100-MkII and MkIII cables (and charge the batteries). For the record, my never-used MkII cable is a 2.5mm TRRS to RCA, with shield to sleeve and signal to the lower ring. NC to tip or upper ring. The owner's manual states the digital input jack is TRS. I have not tried to figure out if the jack is really TRS and they just supplied a cable plug that works, but happens to be TRRS. A TS plug might not work.
My never-used MkIII digital input cable is 3.5mm TS to RCA, wired normally, although the manual says the input jack is TRS.
pic: