By the time 2018 is done, New Jersey will officially have a 10th area code, as 640 will take over some of the space currently held by the 609 code.

Preparations for the new area code started in June and the new code will not go into effect until September, but there will be some noticeable changes for people calling to and from the 609 area. The changes will start Jan. 20 during what the North American Numbering Plan Administration calls the "permissive dialing period."

The area code overlay will stretch from Princeton and Trenton to Atlantic City and Hammonton.

It was predicted that the 609 area code would run out of phone numbers by the third quarter of the new year. The new code comes almost a decade after the 856 area code was added to the 609 area.

From Jan. 20 until Aug. 18, people can call numbers in the affected area using either the seven-digit or 10-digit numbers. Though the seven-digit numbers will work, people are encouraged to use the 10-digits to get used to the approaching changes, the Administration said.

Phone numbers with the new area code can be ordered starting on July 13, and the code is expected to be activated by Sept. 17 at the earliest, according to the administration.

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