> 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/tmedia-documentation/configuration/configure-nfas.md).

# Configure NFAS

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

ISDN-PRI signaling can be configured for your system. To do so, you must create a new ISDN stack.

Integrated Systems Digital Network (ISDN) is a circuit-switched telephone system that integrates voice and data on the same lines. Tmedia and Tdev systems can be configured to provide an ISDN signaling stack on the trunks of one or more units to meet your system configuration requirements.

To create a new ISDN stack:

1- Click **ISDN** in the navigation menu, under the Signaling header

![ISDN NFAS 0](https://docs.telcobridges.com/w/images/8/85/ISDN_NFAS_0.png)

2- Click **Create New ISDN Stack**

![ISDN NFAS 1](https://docs.telcobridges.com/w/images/5/5a/ISDN_NFAS_1.png)

3- Create the new stack:

**Note:** TelcoBridges offers several ISDN variants, four of which support NFAS. By clicking on 'Create' you confirm the line service and in the case of ISDN variants which support NFAS you are permitted to add additional line services.

* Verify that the box labeled **Enabled** is checked
* Enter a **name** for the new ISDN stack
* Select a **variant** to associate with the stack
* Determine whether the stack will operate on the **user side**, or the **network side**
* Select a **line service**
* Click **Create**

![Create ISDN Stack 2 a](https://docs.telcobridges.com/w/images/8/87/Create_ISDN_Stack_2_a.png%E2%80%8E)

4- Verify that the **"ISDN stack was successfully created"** message appears

![ISDN NFAS 3](https://docs.telcobridges.com/w/images/7/7e/ISDN_NFAS_3.png)

5- Create a backup line:

* Click on the **Available** line on the righthand side of the screen, and select the arrow to add it to the **Current-Line Services**. Up to 20 line services can be added in one NFAS group.
* Select the line service that will be used as a **D-channel** backup by this ISDN stack instance.
* Click **Save**

![ISDN NFAS 4](https://docs.telcobridges.com/w/images/2/21/ISDN_NFAS_4.png)

6- Verify that the **"ISDN stack was successfully updated"** message appears, and that the new **trunk** line is listed in the **ISDN Stack List**

![ISDN NFAS 5](https://docs.telcobridges.com/w/images/2/24/ISDN_NFAS_5.png)

**Path**

```
/configurations/@[configuration_name]/hardware_units/@[hardware_name]/isdn_stacks/@[isdn_stack]
```

**Parameters (text)**

```
/configurations/@[configuration_name]/hardware_units/@[hardware_name]/isdn_stacks/@[isdn_stack]
dchannel_bkp_line_service = ""
enabled                   = true
line_services             = [ "@[line_service_name]" ]
name                      = "FNT01"
side                      = "User"
variant                   = "NET5"

/configurations/@[configuration_name]/hardware_units/@[hardware_name]/isdn_stacks/@[isdn_stack]/advanced_parameters
force_wake_up = false
options       = 0

/configurations/@[configuration_name]/hardware_units/@[hardware_name]/isdn_stacks/@[isdn_stack]/timers
t301_timer         = "3 minutes"
t302_timer         = "15 seconds"
t303_timer         = "4 seconds"
t304_timer         = "20 seconds"
t305_timer         = "30 seconds"
t307_timer         = "3 minutes"
t308_timer         = "4 seconds"
t309_net5_timer    = "6 seconds"
t309_timer         = "90 seconds"
t310_network_timer = "10 seconds"
t310_user_timer    = "30 seconds"
t313_timer         = "4 seconds"
t316_timer         = "4 seconds"
```

**Parameters (json)**

```
{
  "advanced_parameters" : {
    "force_wake_up" : false,
    "options" : 0
  },
  "dchannel_bkp_line_service" : "",
  "enabled" : true,
  "line_services" : [
    "@[line_service_name]"
  ],
  "name" : "@[isdn_stack]",
  "side" : "User",
  "timers" : {
    "t301_timer" : "3 minutes",
    "t302_timer" : "15 seconds",
    "t303_timer" : "4 seconds",
    "t304_timer" : "20 seconds",
    "t305_timer" : "30 seconds",
    "t307_timer" : "3 minutes",
    "t308_timer" : "4 seconds",
    "t309_net5_timer" : "6 seconds",
    "t309_timer" : "90 seconds",
    "t310_network_timer" : "10 seconds",
    "t310_user_timer" : "30 seconds",
    "t313_timer" : "4 seconds",
    "t316_timer" : "4 seconds"
  },
  "variant" : "NET5"
}
```

### List of Parameters

* [Enabled](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/enabled/README.md)
* [Name](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/name/README.md)
* [Line Service](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/line-service/README.md)
* [Variant](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/isdn-variant/README.md)
* [Side](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/side/README.md)

**Advanced Parameters**

* [Options](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/parameter-options/README.md)
* [Force wake up action](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/parameters/force-wake-up-action/README.md)


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