The Executone MDF panel was custom-made by Siemon Company for use with Executone systems. There's nothing particularly fancy about them; just a more convenient way to use double-ended cables for the installation. Electrically, all pairs from the 25 pair cables land directly on the clips of the 66 block. You can use either their MDF panel or a traditional block and still accomplish the same thing.

As for the "all pairs are white and blue" question, it really doesn't matter. This was a factory assembly and as long as the input and output was the same, there was really no significance to the wire colors.

Ed Vaughn, MBSWWYPBX