All of the pole lines that you see here carried telegraph communications, a few years before the invention of the telephone.

It is not known what types of insulators were used here however the primary population of them probably were Brookfields (since their manufacturing plant was local). There also may have been Tillotson-lettered insulators upon pole lines in NYC as you see here since their main office also was on Broadway. This company was a well-known source of telegraph supplies.

In any instance it is nice looking at real photos of street scenes like this because we have a glimse of how the vintage insulators of the day connected with the wires that made communication possible with many places over the world.