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International Point Code Numbering



International Signalling Point Codes (ISPCs) are 14-bit binary codes used to establish direct SS7 signalling links and interconnection with overseas networks. The 14 bits of the ISPC are commonly represented by three decimal numbers (e.g. 5-047-0):
  1. the first decimal, with the range of 0 to 7, represents the three (3) most significant bits; It identifies world geographical zone

  2. the second decimal string, with the range of 000 to 255 represents the following eight (8) bits; The sub-field of 8 bits identify a geographical area or network in a specific zone.

  3. and the third decimal, with the range of 0 to 7, represents the three least significant bits. The sub-field of 3 bits (CBA) should identify a signalling point in a specific geographical area or network. The combination of the first and second sub-fields could be regarded as a signalling area/network code (SANC).

14 bit Point code = <3 bits World Geographic Zone><8 bit Geographical Area or Network><3 bits Signalling Nodes identifier in a specific geographical area or network>
ITU-T International Point Code Format
Following are rules for International Point Codes allocation as defined by CCITT :
  1. Each country (or geographical area) should be assigned at least one signalling area/network code (SANC).

  2. Two of the zone identifications, namely 0 and 1 codes, are reserved for future allocation.

  3. The system of international signalling point codes (ISPC) will provide for 6 * 256 * 8 (12288) ISPCs.

  4. If a country (or geographical area) should require more than 8 international signalling points, one or more additional signalling area/network code(s) (SANC) would be assigned to it.

  5. The assignment of signalling area/network codes (SANC) is to be administered by the CCITT. The assignment of signalling point identifications in the sub-field (CBA) will be made by each country (or geographical area) and the CCITT Secretariat notified.

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