NEwtown, NEvins, or NEptune 9-9389. Murphy Fence Inc.
I do not know which NE exchange this sign displays, but it is probably NEwtown, NEvins, or NEptune.

ALgonquin-4-2700, near Union Square
I have passed by this building over a hundred times, so I was chagrinned to pass by in mid-2010 and see this old ALgonquin telephone exchange name phone number sitting in plain sight on the side of this old building. I was relieved to find that my observations skills were not as poor as I thought. This old number was revealed after a demolition of a building next door.

Discarded Umbrella Carcasses, NYC

WAlker 5-2985. John De Lorenzo & Bro.