Configuring Sinch Register Authentication Trunk
Before proceeding with the next steps, you need to purchase a DID on the Sinch platform.
Create a SIP Trunk on the Sinch Platform
To create a new SIP trunk on the Sinch platform, follow these steps.
Step 1: Create an Elastic SIP Trunk
Sign in to your Sinch account.
In the left navigation menu, go to Elastic SIP Trunking > Trunks.
Click Create New SIP Trunk.

Step 2: Configure the SIP Trunk
After you click Create New SIP Trunk, the SIP trunk creation page is displayed. On this page, you can define the trunk name and create the SIP domain that will be used to route calls through the trunk.

In the SIP Trunk Name field, enter a clear and descriptive name for the trunk.
Use a name that helps you distinguish this trunk from other SIP trunks in your Sinch account.
Create the SIP Domain that will be used when sending calls to this trunk.
The value you enter becomes the base domain name, and Sinch appends
.pstn.sinch.comto it.For example, if you enter:
mycompany, the fully qualified SIP domain becomes:mycompany.pstn.sinch.comClick Continue to proceed to the SIP endpoint configuration.
Step 3: Configure the SIP Endpoint
A SIP endpoint defines how Sinch sends calls to your PortSIP PBX. It also authorizes your PBX to send outbound calls through the SIP trunk by using either a trusted public IP address or SIP registration credentials.

Click Add an Endpoint to configure a SIP endpoint now.
After you click Add SIP Endpoint, the endpoint configuration page is displayed.
Choose the endpoint type.
Each SIP endpoint can be configured in one of the following ways:
Static IP address: Use this option when your PortSIP PBX has a fixed public IP address. Sinch will authorize traffic from this IP address.
SIP registration: Use this option when your PortSIP PBX registers to Sinch using SIP authentication credentials.
For this guide, select SIP registration to configure a Register Based SIP trunk for PortSIP PBX.
Step 4: Configure the Registered Endpoint
In the Add New SIP Endpoint dialog, select Registered.
Enter a name for the endpoint.
Select the transport protocol.
If you require encrypted SIP signaling, select TLS.
Set the priority for inbound call routing.
Priority is used when multiple endpoints are configured.
Select the credential that PortSIP PBX will use to register to Sinch.
The credential provides the SIP username and password used for registration.
If no credential has been created yet, click Manage Credentials and create one.

Step 5: Complete the SIP Endpoint Configuration
Configure the endpoint priority and complete the SIP trunk setup.
Leave Priority set to the default value of
1, unless you need to configure multiple SIP endpoints for failover or load sharing.Priority controls how Sinch routes inbound calls when multiple SIP endpoints are configured.
The endpoint with the lowest priority value receives inbound calls first.
Endpoints with higher priority values receive calls only if the primary endpoint is unavailable.
If multiple endpoints have the same priority, Sinch distributes calls between them using round-robin routing.
Click Create to finish creating the SIP endpoint.
Review the endpoint settings.
If the settings are correct, click Next to continue.
To make changes, click the endpoint name to reopen and edit the endpoint configuration.

Step 6: Configure Outbound Call Settings
After configuring the SIP endpoint, configure the outbound call settings for the SIP trunk.

Configure Country Permissions if needed.
This setting controls which countries or regions can be called through the trunk. By default, calls to the United States, Canada, Puerto Rico, and the U.S. Virgin Islands are allowed.
Configure outbound call authentication.
To send calls to the PSTN, you must use either Access Control List (ACL) or Digest Authentication.
ACL allows calls only from approved IP addresses.
Digest Authentication uses SIP credentials to authenticate calls.
If you use ACL, add the public IP address of your PortSIP PBX.
Calls from allowed IP addresses are accepted. Calls from other IP addresses are rejected with SIP
403 Forbidden.
Step 7: Create and Add an ACL
Click CREATE NEW ACL to open the ACL creation wizard.

Enter a name for the ACL.
Enter the static public IP address of your PortSIP PBX in CIDR format.
For a single public IP address, use
/32. For example:203.0.113.10/32Review the IP address range shown at the bottom of the wizard.
This confirms which IP addresses will be allowed.
Click CREATE.
You can add more IP address ranges to the ACL later if needed.
After the ACL is created, select it from the drop-down menu and add it to the SIP trunk.

Step 8: Configure Inbound Call Settings
Enable CNAM if you want Sinch to retrieve and pass caller name information for inbound calls to your numbers.

Note: CNAM is optional and may incur additional charges.
Click Finish to complete the SIP trunk setup.
Your SIP trunk is now ready. You can now configure PortSIP PBX to use the SIP domain you created and send outbound calls through the trunk.
Configure Register Authentication Trunk in PortSIP PBX
The Register Authentication Sinch trunk corresponds to a Register-Based Trunk in PortSIP PBX.
❗Important Register-Based Trunks must be configured at the System Administrator level. Once successfully configured, the trunk can be shared with one or more tenants.
Step 1: Create the Register-Based Trunk
Sign in to the PortSIP PBX Web Portal as a System Administrator.
Navigate to Call Manager > Trunks.
Click Add, then select Register Based Trunk.

Step 2: Configure Basic Trunk Settings
Enter the following information:
Name Enter a friendly name for the trunk (for example,
Sinch-Reg-Trunk).Brand Select the Sinch.
Enter the domain name that you created in the Step 2: Configure the SIP Trunk for Hostname. In case is
mycompany.pstn.sinch.com.DID Pool (For create trunk at Tenant Admin level only) If this trunk is being configured at the Tenant Administrator level, specify the Sinch DID numbers assigned to this tenant.
❗Important
The tenant can use only the DID numbers in its DID pool to:
Create inbound and outbound call rules
Configure outbound caller IDs for extensions
DID Pool Format Examples
Click Next to continue.

Step 3: Configure Trunk Credentials
Enter the credentials created earlier when you created the Sinch SIP connection:
Authentication Name Enter the username configured in the Step 4: Configure the Registered Endpoint.
Password Enter the corresponding password.
Click Next to continue.

Step 4: Configure Trunk Options
Max Concurrent Calls Specifies the maximum number of simultaneous calls that PortSIP PBX can establish using this trunk.
Adjust this value based on your Sinch service plan and expected call volume.
Leave all other options at their default values unless you have specific requirements.
Click Next to continue.

Step 5: Assign Tenants and DID Pool (For create trunk at System Admin level only)
❗Note This step is available only when configuring the trunk at the System Administrator level.
Assign the trunk to one or more tenants.
Provide Sinch DID numbers to each tenant using the DID Pool.
❗Important
Each DID can be assigned to only one tenant.
A tenant can use only the DID numbers in its DID pool to:
Create inbound and outbound call rules
Configure outbound caller IDs for extensions
DID Pool Format Examples
Click OK to save the configuration.

Expected Result
The trunk configuration is complete.
The trunk status will display Online in the trunk list.

Next Steps
You can now proceed to Configuring Outbound & Inbound Calls to complete your call routing setup.
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