> 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/transmission-and-lines/clocking.md). # Clocking The clock is a necessary component of a TDM network. Synchronizing your system with the right clock, allows it to offer good sound quality. ### Clock Sources [Tmedia](https://telcobridges.com/media-gateways/products/tmedia-gateways/) can synchronize its TDM network on 3 types of clock sources: * BITS * [Line Service](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/transmission/line-service/README.md) * [SONET/SDH Interface](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/protocols/sonet-sdh-interfaces/README.md) Clock type is determined by the Tmedia model. Clock availability is indicated in the following table: | Models | Clock Source Type | Clock Source Type | Clock Source Type | | ----------------------------------------------------------------------------------------- | ----------------- | ------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ | | Models | BITS | [Line Service](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/transmission/line-service/README.md) | [SONET/SDH Interface](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/protocols/sonet-sdh-interfaces/README.md) | | [TMG800](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg800/) | ✗ | ✓ | ✗ | | [TMG3200-RJ](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg3200/) | ✗ | ✓ | ✗ | | [TMG3200-TE](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg3200/) | ✗ | ✓ | ✗ | | [TMG3200-DS3](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg3200/) | ✓ | ✓ | ✗ | | [TMG3200-STM1](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg3200/) | ✓ | ✓ | ✓ | | [TMG7800](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg7800/) | ✓ | ✓ | ✓ | ### Clock Redundancy [TMG-CONTROL](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/concepts/tctrl/README.md) enables you to configure system clock references list using the [Web Portal](https://github.com/telcobridges-main/tmedia-wiki/tree/main/tmedia/configuration/web-portal/README.md). Clock redundancy is accomplished by configuring at least two valid clock references in the system. [TMG-CONTROL](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/concepts/tctrl/README.md) will scan the clock references list until it finds a valid one. If the active clock source becomes unavailable, [TMG-CONTROL](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/concepts/tctrl/README.md) will select the next preferred valid clock source. Clock recovery, which means that the system will switch back to a more preferred clock source if it becomes available again, is an option that is available using the [Web Portal](https://github.com/telcobridges-main/tmedia-wiki/tree/main/tmedia/configuration/web-portal/README.md). It is worth mentioning that the [TMG7800](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg7800/) clock is distributed through the system using the TMS network. The following image is an example of a [TMG7800](https://telcobridges.com/media-gateways/products/tmedia-gateways/tmg7800/) system containing 3 source references: ![TMG7800 System With 3 Clock References](https://docs.telcobridges.com/w/images/7/77/Ha_Clock_Setup.png) Even if clock source #1 becomes unavailable, clock source #2 will synchronize the TDM network, as shown in the next example: ![TMG7800 System With 3 Clock References](https://docs.telcobridges.com/w/images/8/85/Ha_Clock_Setup_Failure.png) --- # 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 dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://prosbcdocs.telcobridges.com/telecom-references/transmission-and-lines/clocking.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.