That cable you have is definitely telco special as I have seen numerous times a 2 pair in black used by Verizon in NYC.
It has Verizaon printed on the jacket.
I love the way I have seen it put in a couple of times, one guy is on the floor they need to install a new line on, he stands at the window with the box of cable and grabs the loose end, he then proceeds to drop the box out the window to his partner on the sidewalk, they fasten it at the top and bottom as far as they can reach without a ladder then penetrate thru a hole drilled in the window sill, and staple away to the location.
