back in the day when you ordered a rj21x theyed stack your numbers sequentially so you could plug directly into you pbx and you'd have instant phone system perfect world kinda thing ( you'd wind up cross connecting from the block anyway
because how many pbxs pinned out that way ?) in mass you used to put a orange vendor sticker on the wall were you wanted it and new england tels special services guy would do his best to install it 100 feet away from that sticker don't know why we bothered...