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National authorities for the assignment of ITU-T T.35 terminal provider codes

What is ITU-T Rec. T.35?

The binary coded control procedures used in different terminals defined in the G, H, T and V series of terminals allow for the inclusion of non-standard extensions in addition to the standard facilities defined in each Recommendation. All that is required is the allocation of a unique code to each terminal provider who includes such non-standard facilities. Rec. ITU-T T.35, entitled "Procedure for the allocation of ITU-T defined codes for non-standard facilities", defines the mechanism for the allocation of ITU-T defined code for such non-standard facilities.

This mechanism uses three types of codes:

The ITU-T T.35 country codes are defined within ITU-T T.35 itself (and regularly maintained by ITU-T), and the terminal provider oriented codes are defined by the manufacturer. However, the responsibility for the allocation and management of the terminal provider code lies with the national Administration for telecommunications matters within the country where the manufacturer is located, or with a national body designated by this Administration.

Database of national authorities

In order to provide a centralized list of national authorities for the assignment of ITU-T T.35 terminal provider codes, and to assist manufacturers in obtaining such codes, ITU-T is tasked with maintaining a database of the different national T.35 manufacturer code assignment authorities. ITU-T relies on the information that is to be provided by the different Administrations to the Director of the TSB. The current database was created based on the replies received to TSB Circular 184 (12 September 2003) and its Addendum 1 (30 July 2004), and published in the Annex of ITU-T Operational Bulletin 1001 (2012-04-01).

T.35 manufacturer code assignment authority database

Your country not on the database, or updates are needed?

In case your country is not in the database, we suggest that you contact your national Administration and check with them who is the authority responsible for this registration and what procedure should be followed. Check the contact point in the Global Directory for the ITU Member States (the page may take a minute or so to load).

You may also invite them to provide ITU-T any relevant new or updated information using the Notification Form. The Notification Form can be downloaded in English, French, or Spanish, and provided to the ITU-T Study Group 16 Secretariat preferably by email (, or alternatively by fax (+41-22-730-5853) or via postal mail.