> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/voice-and-media/bridging-service.md). # Bridging Service The "Bridging Service", which is also known as "CTBCAFBridge" was designed to bridge a call correctly, because, it is important to make the correct signaling and media operations. Detailed information can be found in the GRP\_DOC\_CALL\_MANAGEMENT\_-CAF\_CALL section. ### Features **Ringback tone** * The ringback tone is the tone a caller ears when waiting for a subscriber to answer. Detailed information can be found in the CAFCallRingbackTone block who’s default implementation will look in the configuration file for ringback tones **Follow me** * A follow me feature maps an incoming number to multiple outgoing numbers. When a call is made to such a number the system is expected to make all outgoing call attempts and cancel all other attempts when one has answered. Detailed information can be found in the CAFCallFollowMe behavior who’s default implementation will look in the configuration file for outgoing numbers to try. **Fax relay** * A [fax relay](https://telcobridges.com/learning/sip-trunking/fax-over-ip-t38/) feature switches to the appropriate transport for fax transmission. This is only needed with TDM/VOIP bridges because the problem fax relay addresses is caused by compressed audio. Detailed information can be found in the CAFCallFaxRelay. ### Usage This service is used by the [Telephony Application](/telecom-references/developer-reference/caf/telephony-application.md). ### Caveats For now, protocol specific bridging (e.g., adding ISUP information elements in the SDP body) is not implemented but it should be in the near future as this is required by a lot of applications. Of course it may be implemented by clients since all the tools for doing it are provided. *** Return to the Toolpack [User Guide](https://prosbcdocs.telcobridges.com/tmedia-documentation/other-pages/getting-around-the-portal/user-guide) --- # 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://prosbcdocs.telcobridges.com/telecom-references/voice-and-media/bridging-service.md?ask=&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.