> 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/ss7/ss7-backward-call-indicator.md).

# SS7 Backward Call Indicator

The Backward Call Indicator (BCI) signals information about the call setup to the call originator. You have, for example, the "Charge Indicator" which indicated if a call should be charged.

It is a 16 bits field (see Q.763, section 3.5) value passed in the ACM and/or the ANM.

### TelcoBridges and BCI

The TelcoBridges platforms can insert or override the default values sent for the BCI. This is configured in the [profiles](https://tmediadocs.telcobridges.com/other-pages/protocol-stacks-sip/creating-profiles).

Default value for this field is described in Hexadecimal with bits in this order: (HG-FE-DC-BA-PO-N-M-L-K-J-I)

Default value for this field is Hexadecimal **0x5404** (01-01-01-00-00-0-0-0-1-0-0) as seen in the table.

| Bits name | Bit#  | Name                              | default value | Meaning                                   |
| --------- | ----- | --------------------------------- | ------------- | ----------------------------------------- |
| HG        | 15-14 | End-to-end method indicator       | 01            | pass-along method available               |
| FE        | 13-12 | Called party's category indicator | 01            | ordinary subscriber                       |
| DC        | 11-10 | Called party's status indicator   | 01            | subscriber free                           |
| BA        | 9-8   | Charge indicator                  | 00            | no indication                             |
| PO        | 7-6   | SCCP method indicator             | 00            | no indication                             |
| N         | 5     | Echo Control Device indicator     | 0             | incoming echo control device not included |
| M         | 4     | ISDN access indicator             | 0             | terminating access non-ISDN               |
| L         | 3     | Holding indicator                 | 0             | holding not requested                     |
| K         | 2     | ISDN user part indicator          | 1             | ISDN user part used all the way           |
| J         | 1     | End-to-end information indicator  | 0             | no end-to-end information available       |
| I         | 0     | Interworking indicator            | 0             | no interworking encountered               |

The default value can be overridden with a mask **Default backward call indicator enforce mask**. All mask bits with 0 will take the default value. All mask bits with 1 will override with the **Default backward call indicator**.

The configuration allows to send the BCI in the ANM (SS7 answer) in addition to sending it in the ACM (SS7 Address complete). Use the option **Force backward call indicator in ANM**.

The BCI value can also be modified in the [Routing Scripts](/telecom-references/developer-reference/routing-scripts.md)

### Related actions

**Refer to the appropriate Toolpack release:**

* [Modify TDM SS7 profile](https://tmediadocs.telcobridges.com/other-pages/other/modifying-tdm-ss7-profile-settings)

### References

* Q.763 Signaling System No.7 - ISDN user part format and codes, section 3.5


---

# 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/ss7/ss7-backward-call-indicator.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.