One of the more frequently asked questions is, "Why are there 5 separate offices (1 in each borough)? "It was determined early in this century that the vital nature of fire alarm offices required that they be free from disruptions, natural or otherwise. This mandated their isolated, though central, locations.
Another benefit is that it allows for specialization. For example, a person driving in his car on the Belt Pkwy sees a fire. He calls and says he sees a house burning across the highway from K-Mart. He lives in New Jersey and can't describe the location any better. If that call is answered by a dispatcher who has lived their entire life in the Bronx, he'll have a hard time trying to figure out where the K-Mart is; whereas a Brooklyn native can pinpoint the location.
Source:
http://www.fdnewyork.com/article.asp