Point Codes and Dialogic Signaling Products
Point Code Formats
A point code (or 'pointcode') is a unique identifier for a SS7 signaling point, and is used at the MTP3 layer for routing signaling messages across SS7 networks. Pointcodes are issued on a per country basis by different telecom administrations to make sure that each number is unique.
Pointcodes are 2 or 3 byte numbers, but vary in format across the World. In the USA, pointcodes follow an ANSI standard that allocates 24 bit numbers. In Europe and much of the rest of the World, the ITU standard is used extensively, and this uses 14 bit codes. There are also country-specific formats for China (ANSI variant) and Japan (24 bit). It is worth noting that when signalling crosses country boundaries, it is usually necessary for a signalling gateway bridge between 'two worlds' perhaps with a 14 bit point code on one side and a 24 bit point code on the other.
Point codes can be written as decimal numbers, in hex, or in a dashed-decimal format similar to IP addresses, for example: '1-232-7'.
ITU pointcodes are 14 bits and are split into three parts of 3, 8 and 3 bits (sometimes referred to as 3-8-3 format). So for example:
If we write that in binary:
001-11101000-111 (in hex 1-E8-7)
So if we run all the bits together:
00111101000111 => 00 1111 0100 0111 => 0F47
So the decimal form of this pointcode would be 3911.
ANSI pointcodes are 24 bits, following the 8-8-8 format, so for example:
In binary, it would be:
00010100-00011001-00001110 (14-19-0E in hex)
These are easier to convert to decimal, as the bits are already laid out in eights, so 14190E => 1317134.
Pointcodes in Dialogic® Distributed Signaling Interface (DSI) Components
Distributed Signaling Interface (DSI) Components (such as Dialogic®
DSI Signaling Interface Unit and Dialogic®
DSI Protocol Stacks) specify point codes as a single integer (which may be in decimal or hex), so it may be necessary to convert a customer's 3-8-3 or 8-8-8 numbers to the integer/decimal/hex format before changing the CONFIG.TXT file. The MTP configuration allows you to select different formats of point code, including ITU14, ITU16, ITU24 and ANSI24. The point code numbers are still specified as an integer, but the protocol software changes the interpretation. In the CONFIG.TXT, the command MTP_CONFIG controls point code format via the options field. For configuration using the message interface, MTP_MSG_CONFIG is used.
IMG Integrated Media Gateway configurator (GC EMS/ ClientView) allows you to choose between a variety of formats. Whenever you enter point codes in the configurator, you have a choice to enter in formatted (n-n-n) or decimal. You can click between the two to convert formats. The point code numbers are shown in the configuration according to your choice of format. Selection of the ISUP variant (ITU 97, 93; CCITT 88; ETSI V1,V2,V3; ANSI 95,97) also changes the point code interpretation, so for example:
Point code 1991 under ITU-97 will be converted to 0-248-7 where under ANSI-97 it would be interpreted as 0-7-199
If you want to convert point codes between different formats, there is an online converter at: http://jhartman.webd.pl/pc/
selectable between 24-bit and 14-bit formats. However, please note that Dialogic is not responsible for your use of this converter, nor for your choice to do so or for any information provided thereby.
First published: 19-Sep-2008
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