> ## Documentation Index
> Fetch the complete documentation index at: https://developers.nlpearl.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Custom VoIP Integration
> Learn how to integrate your own VoIP service with NLPearl.AI.
Integrate your own VoIP service with NLPearl to use your existing phone numbers for inbound and outbound calls. This flexibility allows you to leverage your current VoIP infrastructure while benefiting from NLPearl.AI’s advanced features.
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### How to Integrate Your Custom VoIP Service
To integrate your custom VoIP service, follow these steps:
Start by clicking your **profile card** (1) at the bottom-left corner of the sidebar. This opens the Settings panel.
From there, go to the **Phone Numbers tab** (2) to manage or purchase phone numbers linked to your account.
Inside the Phone Numbers tab, locate and click the Custom VoIP button in the center of the screen to start setting up your own provider.
Enter the phone number you want to associate with this custom VoIP configuration.
It can be any number – it's just for display (DID NUMBER/extension, etc.).
Decide whether this number will be used for inbound, outbound, or both. You can configure both flows independently afterward.
### Inbound Configuration Settings
Secures your VoIP traffic by encrypting both the signaling (via TLS) and media (via SRTP). Activate this toggle **only** if your VoIP provider requires it.
**When to Enable It:**
* Your SIP provider specifically mentions TLS or SRTP support.
* You want to ensure secure, encrypted voice communication (e.g., for compliance or privacy reasons).
**When to Leave It Off:**
* Your provider doesn’t support TLS/SRTP — enabling it may block calls or cause failed connections.
* You’re using basic test environments or local SIP servers without encryption.
Choose one of the following methods to authorize your outbound VoIP traffic:
**IP Address Authentication:**
Allow traffic from specific IP addresses — ideal if your VoIP infrastructure has a static IP.
IP Address:
Enter the public IP address(es) of your SIP servers so we can accept and process requests from them.
**Credentials Authentication (Optional):**
Use a username and password to authenticate each outbound SIP request.
Username: Alphanumeric string (max 32 characters)
Password: At least 12 characters, with 1 uppercase, 1 lowercase, 1 digit, and 1 special character.
This method is useful if your infrastructure is cloud-based and IPs can change, or you want multi-tenant control.
Once you save the inbound configuration, you will receive a SIP Domain to connect. You will need to add this SIP Domain to your VoIP configuration so it can transfer the call to our platform. If you choose Credentials Authentication, make sure to also include the username and password you select in your VoIP settings.
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### Outbound Configuration Settings
Secures your VoIP traffic by encrypting both the signaling (via TLS) and media (via SRTP). Activate this toggle **only** if your VoIP provider requires it.
**When to Enable It:**
* Your SIP provider specifically mentions TLS or SRTP support.
* You want to ensure secure, encrypted voice communication (e.g., for compliance or privacy reasons).
**When to Leave It Off:**
* Your provider doesn’t support TLS/SRTP — enabling it may block calls or cause failed connections.
* You’re using basic test environments or local SIP servers without encryption.
This is the address your outbound calls will be sent to — typically provided by your VoIP provider.
Enter the SIP trunk URL where your calls should be routed.
This is the SIP user identity used in the “From” header of your outbound SIP requests. It's how your VoIP system identifies the origin of the call.
What to enter:
You can use one of the following formats depending on your provider:
* A SIP username (e.g. `caller01`)
* A DID or phone number in `E.164` format (e.g. `+1234567890`)
* An extension (e.g. `201`)
* A SIP URI (e.g. `caller01@example.com`) — less common
Select the geographic location (network edge) closest to your VoIP infrastructure to optimize call routing and reduce latency.
This toggle enables or disables call transfers using the SIP REFER method.
When enabled, it allows:
* Transferring a live call from one destination to another without media proxying
* Offloading media streams directly between endpoints
* Reducing latency and server load
**Credentials Authentication:**
Use this method if your VoIP provider requires username/password credentials to authenticate outbound calls.
Username:
This is the identifier associated with your SIP account.
Password:
A secure password used to authenticate the SIP user.
Make sure it meets your provider’s security requirements (e.g. minimum 12 characters, including upper/lowercase letters, a number, and a special character).
**Header-Based Authentication:**
Use this method if your VoIP provider requires custom headers for SIP request authentication.
Header Key:
This is the name of the custom SIP header field expected by your provider (e.g., X-Custom-Auth, X-Access-Token, etc.).
Header Value:
The corresponding value used to validate the request (e.g., a token, API key, or static secret).
Example: AuthZ-87!t!link
Header-based auth is typically used for advanced integrations or when SIP gateways are behind proxies/firewalls that don’t support IP or credential-based auth.
Ensure this matches exactly what your provider expects, as even small typos (like case or symbols) can lead to rejections.
You can add several key-value pairs if needed — for example, to meet multi-token security policies.
* **IP Address Allow List:**\
**IP Address:** See [Twilio's SIP Trunking IP Addresses](https://www.twilio.com/docs/sip-trunking/ip-addresses).
Once integrated:
* **Assign to Inbound/Outbound:**\
You can assign your custom VoIP phone numbers to inbound or outbound campaigns within NLPearl.AI.
* **Update Configuration:**\
If any changes are needed, you can edit the VoIP settings by accessing the phone number in the Phone Numbers tab.
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### Troubleshooting Tips
**Connection Issues**: Double-check all configuration settings — especially SIP URLs, usernames, passwords, and IP addresses.
**Authentication Failures**: Make sure the authentication method you've selected matches the one supported by your VoIP provider.
**Provider Support**: If you're unsure about specific requirements, contact your VoIP provider for assistance with configuration.
### Advantages of Custom VoIP Integration
**Flexibility**: Leverage your existing VoIP infrastructure without switching providers or modifying your current setup.
**Global Reach**: Access phone numbers and make calls in any region your VoIP provider supports — ideal for international teams.
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Purchase and manage your **NLPearl-hosted phone numbers** directly — with instant activation and native support.
Explore our **Twilio Integration** to access a broader range of international phone numbers.
**Need Assistance?**\
If you require help with the integration process, please refer to our support resources or contact our support team for guidance.
