> ## Documentation Index
> Fetch the complete documentation index at: https://docs.telzino.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SIP Registration

> SIP Register your Telzino AI agent to an external PBX to send and receive calls.

SIP Registration allows your Telzino AI agent to register to an external PBX or SIP server, enabling it to send and receive calls just like any other VoIP device within your network.

## Configuring SIP Registration

To register your Telzino AI agent with your external SIP system, you'll need the following information:

* **SIP Domain** *(required)*\
  Your SIP domain, usually formatted as something like: `sip.yourdomain.com`

* **Username** *(required)*\
  The SIP username provided by your VoIP service or PBX. Typically, this is your SIP extension. For example: `1001`

* **Password** *(required)*\
  The SIP password associated with your SIP account.

* **Proxy** *(optional)*\
  The SIP proxy address your registration requests should be sent to. If your SIP provider uses a separate proxy or outbound server, specify it here. Example: `proxy.yourdomain.com`

* **Port** *(optional)*\
  The port number used for SIP signaling. Default is: `5060`

* **Transport** *(optional)*\
  The transport protocol used for SIP signaling (`UDP` or `TCP`). Default is: `UDP`

* **Subscribe to Presence** *(optional)*\
  Check this option if your SIP provider supports Message Waiting Indicator (MWI) or Busy Lamp Field (BLF) subscriptions.

### Registrar addresses to allow

Registration requests come from the Telzino proxy pair for your account's region. Allow **both** addresses in your PBX firewall: agents are pinned to one node and fail over to the other.

| Region | Hosts | Addresses |
| - | - | - |
| US | agent-proxy1.use1.oci, agent-proxy1.usw1.oci | `143.47.120.76`, `161.153.52.190` |
| Canada | agent-proxy1.cae1.oci, agent-proxy1.cae2.oci | `192.18.150.64`, `147.15.129.207` |

The SIP Registration tab shows the pair for your region.

### SIP User-Agent

Some PBXs and SBCs only accept registrations from known phone models and reject everything else before even challenging for a password. The optional **SIP User-Agent** field sets the `User-Agent` header the registration carries — enter the string your own phones send, for example `Yealink SIP-T54W 96.86.0.75`. Leave it empty to use the platform default.

### Use DNS SRV

Some proxies publish SRV records and no A record, so a fixed port can never resolve. Turn on **Use DNS SRV** and the port field is hidden: the registration is sent without a port, and the host is resolved by SRV with failover across its targets. As you type the proxy host the form checks its DNS and tells you whether SRV records exist and what the host resolves to, and offers to switch to SRV when it finds records.

### Verify before saving

**Verify** sends a test registration with the values as typed, without saving, from the proxy node that owns the agent, and reports the result: registered, rejected before authentication (typically a User-Agent or address allow-list), bad credentials, no reply, or an unresolvable host — with each leg's status and timing and a **What was sent** panel. The password never leaves the server. One verification per agent every 30 seconds.

## SIP Registration Status

Once your SIP account is registered, the status indicator will display the current registration status:

* `200 OK` means your agent has successfully registered.
* Any other status indicates an issue with registration (e.g., authentication failure, unreachable proxy, or incorrect configuration).

## Example SIP Registration

**Example configuration using a proxy server:**

```
SIP Domain: Telzinoglobal.yourdomain.com
Username: 1001
Password: yourpassword
Proxy: beta.yourdomain.com
Port: 5060
Transport: UDP
Subscribe to Presence: true
```

**Example configuration without a proxy server:**

```
SIP Domain: sip.yourdomain.com
Username: 1001
Password: yourpassword
Transport: UDP
```

Ensure you obtain accurate credentials from your VoIP or PBX provider before configuring SIP Registration.

## Transferring calls via your registered extension

Because Telzino agents register to your SIP server, call transfers are handled using the SIP REFER method. This offers several benefits over using a SIP trunk:

1. The transferred call has the same SIP Call ID as the original call, making it easier to troubleshoot (both legs of the call will be displayed in a typical ladder graph).
2. Once the call is transferred with a SIP REFER, the call is no longer connected to the AI agent and billing stops. In contrast, calling an agent over a SIP trunk usually means that the AI agent bridges the inbound and outbound calls together, staying in the call path of the entire duration.

Your agent can use your SIP registration via the [Call Transfer](https://docs.telzino.com/functions/call-transfer.md) function to dial extensions and other internal destinations. Simply prepend `pbx:` or `ext:` to your transfer destination.

**Example instructions for having your agent transfer to an extension via the Registration:**

```
Please transfer all sales calls to ext:1002
Please transfer all support calls to ext:1005
```


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