Numbering plan structure

Plan Tactical Telephone Systems
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Numbering plan structure. There are several levels in the numbering plan. These are as follows:

National identification number (9YX)

Area code (MYX)

Primary zone/switch location (PRSL) or local exchange (NNX)

Subscriber number XXX or XXXX where--

0-9

0 or 1

2-8

2-9

72-99 (except 80, 81, 90, 91, and 99)

00-99

a. National identification number. NATO members have reached a standardization agreement

(STANAG) to use a unique three-digit national identification (NI) number. This number takes the form

of 9YX (where Y = 0 or 1; X = 0 through 9) for each member country. The NI code serves as the first

three digits of a 13-digit telephone number for NATO intercountry calls. The NI code for the tactical

United States (US) forces is 914.

b. Area code. The next level uses a three-digit area code similar to a commercial area code. This

code takes the form of MYX (where M = 2 geographic areas or such organizations as a division, a corps,

or a larger command area. In assigning tactical area codes, planners should avoid duplicating existing

DSN area codes. The existing DSN area codes are--

312 CONUS

313 Caribbean

314 Europe

315 Pacific

317 Alaska

If tactical and DSN area codes are not duplicated, the switch can distinguish between DSN and tactical

calls by the area code.

c. PRSL or NNX

d. Each MYX area can be partitioned by one of three methods. In method one, the MYX area is

called a PRSL subnetwork. In a PRSL subnetwork, the MYX area can get divided in up to 23 primary

zones or areas switch (PR). In each PR, every switch will have its own unique (SL). PRs can equal 72

through 99, except 80, 81, 90, 91, and 99. (Numbers 80, 81, 90, and 91 are reserved for DSN. PR 99 is

reserved for fixed directory dialing.) Each can contain up to 100 SLs.

e. In an NNX subnetwork, an MYX area can be partitioned in up to 640 switching center (NNX)

codes.

SS 0029

2-2

Index