Sweet Old School Fence Signs Prince Of Petworth September 15, 2009 at 9:39pm IMG_1576, originally uploaded by Prince of Petworth. I wonder why back in the day they used letters for the first two numbers? Was it just easier that way when you’d say, “operator, ring me JO 3-1000”? Anyone know the reason? I thought it was interesting that after noticing this one a couple hours later I found another from a different company.