DDD prefixes for STFC and SCM operators

For STFC operators, it is important to understand how the numbering system evolved. Due to the constant increase in telephone lines, there was a need to adopt some standards, both to increase the number of numerical combinations and to more easily identify some telephone information. In Brazil, the body responsible for standardizing telephone numbering is Anatel. And as an example of the information that we can identify just by analyzing these established patterns, we can mention: identifying the geographic area to which a number belongs, discovering the operator carrying that number (when not ported), identifying the type of call that is being made, in addition to enable easy identification of special numbers. In this article we discuss some examples of how we can identify this information using the national standards established by Anatel.

Fixed telephone prefixes (STFC) and mobile telephone prefixes (SMP)

The telephone number is made up of eight digits, and now nine for some cell phones.

(N8+N7+N6+N5 + N4+N3+N2+N1). Of these numbers, the first four are formed by what we call the operator's identifying prefix. Operators receive a certain range of prefixes – first four digits (N8+N7+N6+N5) – for each location (DDD). To consult the operator of ported numbers, another means of identification must be used, such as the Automatic Telco Identification (ATI).

Of the first four digits, it is the first that defines the type of telephony – fixed or mobile – of this number. It is important to emphasize that the same prefix can be used by different operators but in different areas, as the prefix ranges are distributed taking into account the DDD+prefix. Check out some of these patterns below:

Fixed telephony (STFC)

For fixed telephone operators, the range of prefixes that have numbers between 2 and 5 for the first digit (N8) is intended.

Mobile telephony (SMP)

For mobile phone operators, the range between 6 and 9 is intended (in SP, 5 is also used) for the first digit (N8). From this range it is possible to identify the peculiarity of each of these digits (6-9):

– 9 used for Bands A (96 to 99) and B (91 to 94);

– 8 used for bands D and E;

– 7 intended for cell phones and Trunking (Nextel);

– 6 used for bands A, B, D and E* (used in SP for mobile telephony from 2008 onwards).

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Caller identifier prefixes

There are also prefixes that identify the type of call (national, international, collect):

– 0 national prefix, used to identify national long-distance calls;

– 00 international prefix, used to identify international long distance calls;

– 90 collect call prefix, characterizes a collect call at the destination.

National area code map (DDD)

Direct Distance Dialing Code, popularly known by its acronym DDD, identifies the geographical region in which the number is registered. To better illustrate the geographic location and its respective DDD, below is the map of DDD's and their geographic location in the national territory.

Provider Selection Code (CSP)

CSP is the code used to select the operator on long distance calls, each operator has its own unique code, e.g.: 21 Embratel, 41 TIM, 14 Brasil Telecom.

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Routing Number (RN) Codes

Routing Number codes are used to identify the service requested by the user, and identify the operator in question. They are classified into three categories, RN1, RN2 and RN3, with RN3 being standardized by Anatel for use in interconnections between telecom service providers. RN2 follows a standard defined internally by each operator, and is used so that call routing is carried out correctly within its network.

RN1 is a standardized numeric code used to identify the provider. It is made up of five digits (N5+N4+N3+N2+N1), the first three of which (N5+N4+N3) are reserved for identifying the type of provider, for STFC operators the first three digits are made up of 551, 552 or 558 and for SMP operators the first three digits are 553. The last two digits are standardized by Anatel, most of which are formed by the provider's CSP code. Download the RN1 code table.

Non-geographical codes

Non-geographic codes are codes that can be used throughout the national territory, these codes were defined by Anatel, they are: 900 where the originator is responsible for paying for the call, 800 where the destination is the one who pays for the call, 500 intended for recording the intention to donation (maximum value of R$ 30.00), 300 originator is responsible for paying for the call.

There are also access codes for public utility services, which are made up of three digits (N3+N2+N1), all of which contain the number 1 as the first digit (N3), characterized by being free calls (when originating from a landline ) for most services, except when making calls to services where the originator is not a customer, such as customer service from STFC telephone companies (103 25, 103 14, 103 20).

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This article was based on information obtained from the Teleco portal, find out more here.