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Prerequisites

  • An active Telnyx account
  • A Telnyx phone number or SIP trunk
  • Access to the Telnyx portal

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Step 1: Create a SIP Connection

  1. Log in to the Telnyx Portal
  2. Navigate to Voice > SIP Trunking (or search for “SIP Connection”)
  3. Click Create SIP Connection

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Step 2: Configure Details

  1. Enter connection details:
    • Name: “TELNYX SIP TRUNK ROUNDED” (or your preferred name)
    • Type: Select FQDN (recommended for Rounded integration)

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Step 3: Authentication and Routing

Choose your authentication method for outbound calls:

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Method A: Credentials (Username/Password)

  • Select Credentials
  • Enter Username and Password
  • Note these credentials for Rounded configuration

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Method B: IP Address Authentication

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Step 4: Inbound Configuration

Configure inbound call routing:

  1. Add FQDN for Rounded routing:

  • DNS record type: SRV
  • FQDN: sip.callrounded.com
  1. Configure other inbound settings:
    • SIP transport protocol: TCP (recommended)
    • SIP region: Europe (or closest to your location)
    • Codecs: G722, G711U, G711A (recommended)

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Step 5: Outbound Configuration

Configure outbound call settings:

Key settings:

  • Outbound voice profile: Default
  • Localization country: Select your country
  • Channel limit: Set according to your needs
  • Caller ID Override: Configure if needed

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Step 6: Associate Numbers

After creating the connection, assign phone numbers:

  1. Go to the Numbers tab in your SIP connection
  2. Click Assign number to add existing numbers
  3. Or purchase new numbers if needed

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Step 7: Configuration in Rounded

In the Rounded interface, configure your SIP trunk:

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Number settings

  • Phone number: Your Telnyx number (e.g., +15551234567)
  • Friendly name: “My Telnyx number”

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SIP Trunk settings

  • Termination URI: sip.telnyx.com
  • Username: Your Telnyx username (if credential authentication selected)
  • Password: Your Telnyx password (if credential authentication selected)

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Step 8: Test the Configuration

  1. In Rounded, create a simple voice agent
  2. Assign it to your Telnyx number
  3. Test:
    • Inbound call: Call your Telnyx number
    • Outbound call: Initiate a call from your agent

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Troubleshooting

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”401 Unauthorized” error

  • Check authentication credentials
  • Verify that authentication is correctly configured

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Inbound calls don’t pass

  • Check the inbound routing configuration
  • Ensure the Rounded URI is correctly configured

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Audio quality issues

  • Check authorized codecs
  • Test different codecs (G.722 recommended)

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“403 Forbidden” error

  • Check the authorized IP list
  • Contact Telnyx to confirm the configuration

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Pricing

Telnyx offers:

  • Competitive rates for international calls
  • No monthly fixed fees for SIP connections
  • Per-second billing
  • Volume-based discounts

See Telnyx pricing grid for more details.

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Support

For help:

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Telnyx Advantages

Competitive rates: Among the cheapest on the market
Global coverage: Over 150 countries
Modern API: Easy integration via REST API
Private network: Dedicated infrastructure for quality

💡 Tip: Telnyx offers excellent quality/price ratio, particularly suited for high volumes.