If I understand correctly what you are trying to accomplish is verifying that the new cable isn’t wired with a polarity reversal. Especially a reversal of one channel relative to the other, per Testpilot’s comment and per the stated intent of the "wiring" section of the writeup you linked to.
If so, and even if you are concerned about absolute as well as relative polarity, it seems to me that all you have to do is to disconnect the cables from the phones and use a multimeter to verify that the wiring of the new cable is the same as the wiring of the old cable.
And if by any chance it is physically possible to insert the cables into the phones with two different orientations, 180 degrees apart, and if the plugs don’t have any markings that would allow you to keep track of which is which, you could temporarily put a small piece of tape on one side of the plugs to keep track of that.
Regards,
-- Al
If so, and even if you are concerned about absolute as well as relative polarity, it seems to me that all you have to do is to disconnect the cables from the phones and use a multimeter to verify that the wiring of the new cable is the same as the wiring of the old cable.
And if by any chance it is physically possible to insert the cables into the phones with two different orientations, 180 degrees apart, and if the plugs don’t have any markings that would allow you to keep track of which is which, you could temporarily put a small piece of tape on one side of the plugs to keep track of that.
Regards,
-- Al