Other codes for telecommunications networks

FICORA administers a wide range of different codes used in telecommunications networks. These include operator codes, Mobile Network Codes (MNC), Network Colour Codes (NCC), TETRA mobile network codes, signalling point codes, CUG codes and Centrex codes.

Operator codes

Operator codes are used for separately specified applications. Currently these include the following:

  • telephone number portability
  • V5 interface
  • the numbering of GT addresses (Global Title) for network elements.

FICORA has issued a decision that assigns the operator codes 89 and 989 for test use.
A list of granted operator codes is available here.

Granted hexadecimal operator codes:

  • Number: 1B, Company: Telavox AB / Telavox Oy, Date: 9.5.2017

Mobile Network Codes (MNC)

Mobile Network Codes (MNC) are used in accordance with GSM standards for identifying a mobile operator in, for example, signalling between a base station and a mobile device and for indicating a mobile operator in base station identification (Cell Global Identification).

A list of granted MNCs is available here.

Network Colour Codes

Network Colour Codes (NCC) are used in accordance with GSM standards in Base Station Identity Codes in the signalling between a mobile device and a base station. The codes are used for identifying mobile operators from different countries in the traffic in border regions where the operators may use overlapping frequency ranges. The use of NCCs is defined in FICORA's numbering regulation.

TETRA Mobile Network Codes

TETRA Mobile Network Codes ((T)MNC) are used for identifying telecoms operators in mobile networks that comply with TETRA standards.
A list of granted (T)MNCs is available here.

Signalling point codes

Signalling point codes are used in identifying network nodes in the Signalling System No. 7 (SS7). To avoid two different nodes in a signalling network having the same signalling point code, each telecoms operator must use the signalling point codes assigned to it in advance. The nodes in the national signalling network are identified with national signalling point codes and the nodes in the international signalling network with international signalling point codes. Messages in the national network are differentiated from those in the international network with a network indicator included in the address field.

CUG codes

In the Closed User Group (CUG) supplementary service, interlock codes are used for verifying that a user belongs to a specific closed user group. The codes are transferred in a telecommunications network in the signalling between centres (SS7 TUP/ISUP). To avoid situations in which two subscribers that belong to different user groups have the same interlock code in the ranges of different telecoms operators, each telecoms operator is assigned its own code range. A telecoms operator allocating interlock codes to closed user groups is only allowed to use the codes in the range assigned to it.

Centrex codes

Providing an extensive Centrex service in the areas of several operators requires that CTX data are transferred in SS7. CTX data include, for example, a group code identifying a certain CTX group. For the Centrex service to function between different telecoms operators, the Centrex group codes may not overlap. For that reason, each telecoms operator is assigned its own range within which it can define the group codes.

Key words: Telephone , Numbering , Telecommunications

Updated 12.09.2017

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