> For the complete documentation index, see [llms.txt](https://tmediadocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tmediadocs.telcobridges.com/telecom-references/ss7-and-signalling/mtp2/mtp2-specification.md).

# MTP2 Specification

TelcoBridges' implementation of the [MTP2](/telecom-references/ss7-and-signalling/mtp2.md) software conforms to the following standards:

* GR-246, Issue 3, T1.111.3 SS7 Signaling Data Link (MTP Level 2), ANSI 1992.
* Q.701 SS7 (MTP), CCITT 1992.
* Q.703 SS7 Signaling Data Link, CCITT 1992.
* JT-Q.703 MTP Signaling Link, TTC recommendation (\*)
* NTT - Q.703 MTP Specifications, NTT recommendation (\*)

(\*) Available only through the TB640 native API as those are not currently supported by layers above (MTP3, M3UA, etc) in the complete Toolpack framework.

The following messages may be received or transmitted by MTP2 across the line interfaces / line services:

* Message Signal Unit (MSU)
* Link Status Signal Unit (LSSU)
* Fill-In Signal Unit (FISU)

### Variants

The following protocol variants are supported:

**MTP2**

* ITU (< ITU BLUE > used for ITU88)
* ITU92( < ITU WHITE > used for ITU92, ITU97, Q767, SINGAPORE and CHINA)
* ANSI88 (used for ANSI88)
* ANSI92 (used for ANSI92, ANSI96 and TELCORDIA)

**MTP3**

* ITU = (88, 92, 97, Q767 and SINGAPORE)
* CHINA
* ANSI = (88 and 92)
* ANSI 96 = (96 and TELCORDIA)

**ISUP**

* ITU = (88 and 92)
* ITU 97
* SINGAPORE
* ANSI 88
* ANSI 92
* ANSI 95
* TELCORDIA 97
* CHINA
* UK
* ETSI
* ETSIV3

#### Protocol variant compatibility

| MTP2    | MTP3    | ISUP                |
| ------- | ------- | ------------------- |
| ITU 88  | ITU     | ITU                 |
| ITU 88  | ITU     | ITU 97              |
| ITU 88  | ITU     | Singapore           |
| ITU 88  | ITU     | Q767                |
| ITU 88  | ITU     | United Kingdom (UK) |
| ITU 88  | ITU     | ETSI                |
| ITU 88  | ITU     | ETSIv3              |
| ITU 88  | China   | China               |
| ITU 92  | ITU     | ITU                 |
| ITU 92  | ITU     | ITU 97              |
| ITU 92  | ITU     | Singapore           |
| ITU 92  | ITU     | Q767                |
| ITU 92  | ITU     | United Kingdom (UK) |
| ITU 92  | ITU     | ETSI                |
| ITU 92  | ITU     | ETSIv3              |
| ITU 92  | China   | China               |
| ANSI 88 | ANSI    | ANSI 88             |
| ANSI 88 | ANSI    | ANSI 92             |
| ANSI 88 | ANSI    | ANSI 95             |
| ANSI 88 | ANSI    | Telcordia           |
| ANSI 88 | ANSI 96 | ANSI 88             |
| ANSI 88 | ANSI 96 | ANSI 92             |
| ANSI 88 | ANSI 96 | ANSI 95             |
| ANSI 88 | ANSI 96 | Telcordia           |
| ANSI 92 | ANSI    | ANSI 88             |
| ANSI 92 | ANSI    | ANSI 92             |
| ANSI 92 | ANSI    | ANSI 95             |
| ANSI 92 | ANSI    | Telcordia           |
| ANSI 92 | ANSI 96 | ANSI 88             |
| ANSI 92 | ANSI 96 | ANSI 92             |
| ANSI 92 | ANSI 96 | ANSI 95             |
| ANSI 92 | ANSI 96 | Telcordia           |


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://tmediadocs.telcobridges.com/telecom-references/ss7-and-signalling/mtp2/mtp2-specification.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.