> 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/configuration/web-portal-3-3/hardware/tdm-network/defining-a-clocking-source.md).

# Defining a Clocking Source

> **Applies to:** Tmedia 3.0, 3.2, 3.3

A network clock is a necessary component of a TDM network. Synchronizing your system to a clock will ensure that a good condition of your system is maintained. It is recommended that you configure an external [clocking](/products/tmedia/features-and-solutions/features/redundancy-and-high-availability/hardware-clocking.md) source for your system.

To configure a clock:

1- Click **Clocking** in the navigation panel

![CreateSystemClock 0](https://docs.telcobridges.com/w/images/9/95/CreateSystemClock_0.png)

2- Click **Create New External System Clock Reference**

![CreateSystemClock 1](https://docs.telcobridges.com/w/images/3/3d/CreateSystemClock_1.png)

3- Create the new clocking source:

* Enter a name for the clock.
* Select the appropriate hardware **adapter**
* Select a **clock reference type**
* Select a **clock reference source**

**Note:** In this example, **Line Service** is selected as the reference type, and a line service is selected as the clocking source.

![CreateSystemClock 3](https://docs.telcobridges.com/w/images/9/94/CreateSystemClock_3.png)

4- Verify that the **System Clock was successfully created** message appears, and that the new clocking source appears in the **External System Clock Reference List**

![CreateSystemClock 2](https://docs.telcobridges.com/w/images/3/3c/CreateSystemClock_2.png)

**Path**

```
/configurations/@[configuration_name]/clocks/configuration
```

**Parameters (text)**

```
/configurations/ @[configuration_name]/clocks/configuration
synchronous_tms_network = true

/configurations/ @[configuration_name]/clocks/configuration/clock_and_link_recovery
use_clock_ref_recovery       = false
use_link_switchover_recovery = false

/configurations/ @[configuration_name]/clocks/configuration/qualify_parameters
qualify_delay                 = "30 seconds"
qualify_recovery_delay        = "3 minutes"
trunk_cvc_anomalies_qualify   = 0
trunk_cvc_anomalies_unqualify = 1
trunk_fec_anomalies_qualify   = 0
trunk_fec_anomalies_unqualify = 1
trunk_los_defects_qualify     = 0
trunk_los_defects_unqualify   = 1
trunk_oof_defects_qualify     = 0
trunk_oof_defects_unqualify   = 1

/configurations/ @[configuration_name]/clocks/configuration/external_clocks/@[clock_name]
clock_ref_source = "@[line_service_name]"
clock_ref_type   = "Line service"
hardware_unit    = "@[hardware_name]"
name             = "@[clock_name]"
priority         = 1
```

**Parameters (json)**

```
{
  "clock_and_link_recovery" : {
    "use_clock_ref_recovery" : false,
    "use_link_switchover_recovery" : false
  },
  "qualify_parameters" : {
    "qualify_delay" : "30 seconds",
    "qualify_recovery_delay" : "3 minutes",
    "trunk_cvc_anomalies_qualify" : 0,
    "trunk_cvc_anomalies_unqualify" : 1,
    "trunk_fec_anomalies_qualify" : 0,
    "trunk_fec_anomalies_unqualify" : 1,
    "trunk_los_defects_qualify" : 0,
    "trunk_los_defects_unqualify" : 1,
    "trunk_oof_defects_qualify" : 0,
    "trunk_oof_defects_unqualify" : 1
  },
  "synchronous_tms_network" : true,
  "external_clocks" : {
  }

  "clock_ref_source" : "@[line_service_name]",
  "clock_ref_type" : "Line service",
  "hardware_unit" : "@[hardware_name]",
  "name" : "@[clock_name]",
  "priority" : 1

}
```

### List of Parameters

* [Name](https://tmediadocs.telcobridges.com/telecom-references/parameter-reference/m3ua#n)
* [Unit](https://tmediadocs.telcobridges.com/telecom-references/parameter-reference/sip#a)
* [Clock Reference Type](https://tmediadocs.telcobridges.com/telecom-references/parameter-reference/tdm#c)
* [Clock Reference Source](https://tmediadocs.telcobridges.com/telecom-references/parameter-reference/tdm#c)


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