Everyone recognizes this number system, (269) 961-7766. It is, of course, a telephone number. The three distinct parts of a phone number are easily identifiable. The first part is the area code, the second part is the exchange, and the third part is a unique four-digit number.
(269) 961-7766
Just as each part of a telephone number has a distinct meaning, a NSN is formatted to convey specific information about the item of supply.
The NSN is a 13-digit code, and it is depicted as: 6240-00-357-7976
The first four digits of the NSN are known as the Federal Supply Class (FSC). For example, 6240 is the FSC for electric lamps. It is used to group like items, which would include fluorescent lamps, incandescent lamps, mercury lamps, and sodium lamps. The next two digits make up the Country of Origin code. This code signifies the country that originally requested the NSN assignment. Codes 00 and 01 are both used to identify the United States. The remaining seven digits are sequentially assigned and are unique to each NSN.