The NANP telephone numbers are 10 digits in length and are composed of three parts (in the format NXX-NXX-XXXX, where N is any digit 2-9 and X any digit 0-9):

# A 3-digit Numbering Plan Area (NPA) code or area code - the first 3 digits - ranging from 200 to 999. Jamaica has been assigned Area Code 876.
# A 3-digit central office (or exchange) code – the second 3 digits - ranging from 200 to 999
# A 4-digit line number - the last 4 digits – ranging from 0000 to 9999 The central office code and the line number, form the directory number, which is the telephone number with which people are most familiar.

Therefore, under each Area code there are approximately 800 central office codes (codes with ‘00’ or ’11’ as the last two digits (e.g. 911) are not normally used as central office codes).

Under each central office code there are 10, 000 line numbers. This provides roughly 8 million (8,000,000) telephone numbers.

Numbers are normally assigned to service providers in blocks of 10,000 (one central office code).

Service provider identification by numbering

From the initial opening up of the telecoms market, prospective entrants had expressed the desire to have telephone numbers that would uniquely identify them and their customers. Currently, with the sharp differences in telephone rates among cellular mobile service providers, the calls have come from others in the local telecoms industry for this unique identification of service providers, mainly to help callers to determine call charges before they make a call. The complaints claim that callers are confused by the present sharing of number ranges among service providers and so are not able to easily identify which service provider they are calling when they dial a number.

This type of exclusive identification of service providers by numbering is called service provider branding or Telco branding. However, regulatory authorities in most countries, even where there are no shortages of numbering resources, do not allow for service provider branding because it impedes rather than facilitates competition. The fact is that it is in direct conflict with number portability which gives customers the ability to keep their existing telephone numbers when changing from one network or service provider to another. Branding could also result in inefficient utilization of numbering resources; this is currently the major branding issue for Jamaica.