Unless you're a bona fide resident of New Jersey with a specific northern New Jersey area code, this number cannot be used. The state of New Jersey's unemployment division breaks down into four main numbers: northern New Jersey, central New Jersey, southern New Jersey and out-of-state calls.
When you dial this number, the system automatically checks the area code of the phone number you're using. If you're calling from a number that is outside of northern New Jersey, the system will not let you proceed. Based on the area code map of New Jersey, this phone number's system will accept 201 and 551 area codes for certain and will probably accept 862 and 973 area codes. 908 area codes are a gray area, as this could fall under either northern New Jersey or central New Jersey.
If your area code is from anywhere else, you will only get an automated message telling you that you cannot use this number for assistance because your phone number is not based in northern New Jersey. Depending on where you're calling from, the number will tell you that you must call the appropriate number in order to receive assistance from anyone. It will then automatically hang up.
This service standard is probably based on the state's need to streamline its unemployment calls and break them down by region. New Jersey is a densely packed state, and having multiple numbers goes a long way in preventing both callers and representatives from getting overwhelmed and having lengthy wait times. The state already requires an overlay code in four different regions because of the high amount of phone numbers. Given that wait times could otherwise exceed a half-hour and the people using these numbers often need immediate help, limiting wait times this way makes a lot of sense.
Still, blocking certain area codes may seem understandably confusing to customers in the modern era. It has the feel of a solution that was created before the cell phone's rise to dominance. People today move in and out of different states regularly, and they often don't change their phone numbers when they move. With New Jersey sharing borders with New York, Pennsylvania and Delaware, it's highly possible for genuine residents of New Jersey to bring a number from one of these states after relocating to the state.
Obviously, given that I could not use this number for anything, I cannot recommend using it unless you have a northern New Jersey area code.