NYS Department of State – Division of Licensing

In the State of New York you must be licensed
“To engage in the business of installing, servicing, or maintaining security or fire alarm systems”

LICENSE LAW
(PDF) 

It is the responsibility of licensees to understand the 
Business of Installing, Servicing or Maintaining Security or Fire Alarm Systems License Law.

Suffolk County requires a Restricted Electricians License to
“Furnish and/or install, repair, maintain, alter or erect all cabling systems 90 volts or less, for computer networking, telecommunications, cable tv, fiber optics, audio and video systems, and home theater systems”