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User can connect phone numbers to Callab AI agents using three methods: phone number screen - add new phone number (phone number types screen)

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Phone Number Types

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1. Callab Managed Numbers

User can purchase and manage phone numbers directly through Callab platform: Features:
  • Purchase numbers from 100+ countries
  • Instant provisioning
  • Included in Callab billing
  • No external account needed
  • Managed by Callab
Best For:
  • Quick setup and testing
  • Simple deployments
  • Users who don’t have existing telephony
How It Works:
  1. Go to Phone Numbers
  2. Click “Add Phone Number”
  3. Select “Callab Managed”
  4. Choose country and number
  5. Complete purchase
Every account gets a free U.S. number for testing. U.S. customers can use this for production.
Billing:
  • Number rental: Varies by country
  • Call costs: Included in Callab subscription
  • No separate telecom billing

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2. SIP Trunk

User can connect existing telephony infrastructure via SIP trunk: Features:
  • Use existing phone numbers
  • Integration with on-premise PBX
  • Enterprise telephony systems
  • Regional/in-country calling
  • Full SIP protocol support
Best For:
  • Enterprise customers
  • Existing PBX systems
  • In-country compliance requirements
  • High-volume deployments
  • Regional infrastructure
Requirements:
  • SIP server or PBX
  • Firewall access (port 5060)
  • MUST whitelist Callab AI IP: 104.197.91.206:5060
  • RTP ports 10000-20000 open
How It Works:
  1. Go to Phone Numbers
  2. Click “Add Phone Number”
  3. Select “SIP Trunk”
  4. Configure gateway details
  5. Whitelist 104.197.91.206 in your SIP server
  6. Test connection
Critical: SIP trunk requires whitelisting Callab AI IP 104.197.91.206:5060 in your SIP server/firewall. Calls will not work without this.
Documentation:

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3. Bring Your Own Twilio (BYOT)

User can connect their existing Twilio account: Features:
  • Use your existing Twilio numbers
  • Keep existing Twilio setup
  • Direct Twilio billing
  • Full Twilio account control
  • Access all Twilio features
Best For:
  • Existing Twilio customers
  • Users with Twilio expertise
  • Custom Twilio configurations
  • Specific Twilio features needed
Requirements:
  • Active Twilio account
  • Twilio Account SID
  • Twilio Auth Token
  • Phone number purchased in Twilio
How It Works:
  1. Go to Phone Numbers
  2. Click “Add Phone Number”
  3. Select “Bring Your Own Twilio”
  4. Enter Twilio Account SID
  5. Enter Twilio Auth Token
  6. Select phone number from account
  7. Save configuration
Billing:
  • Twilio bills user directly
  • Callab does NOT charge for calls
  • User pays Twilio standard rates
  • Check Twilio pricing for costs
Documentation:

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Choosing a Phone Number Type

User should consider: Choose Callab Managed if:
  • You want simple setup
  • You don’t have existing telephony
  • You want single-vendor billing
  • You need quick deployment
Choose SIP Trunk if:
  • You have existing PBX infrastructure
  • You need enterprise features
  • You require in-country routing
  • You have IT team for configuration
  • You need regional compliance
Choose BYOT if:
  • You already use Twilio
  • You want to keep existing Twilio setup
  • You need specific Twilio features
  • You want direct Twilio billing
  • You have Twilio expertise

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Adding Phone Numbers

phone number screen - bring your own twilio (BYOT) creation modal User can add phone number:
  1. Navigate to Phone Numbers section
  2. Click “Add Phone Number” button
  3. Select phone number type:
    • Callab Managed
    • SIP Trunk
    • Bring Your Own Twilio
  4. Complete configuration for selected type
  5. Save phone number

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Phone Number Format

User must use E.164 format for all phone numbers: Format: +[country code][number] Examples:
  • U.S.: +14155552671
  • U.K.: +442071234567
  • Saudi Arabia: +966501234567
  • UAE: +971501234567
E.164 is international phone number format. Always include + and country code.

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Default Testing Number

User gets default number for testing: Free U.S. Number:
  • Automatically assigned to new accounts
  • Used for testing AI agents
  • Twilio-powered
  • Free for testing
U.S. Customers:
  • Can use default number for production
  • Can purchase additional numbers
  • Can switch to SIP/BYOT later
Non-U.S. Customers:
  • Use default number for testing only
  • Must configure SIP/BYOT for production
  • Or purchase country-specific number

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Country-Specific Numbers (Callab Managed)

User can purchase numbers from 100+ countries: Supported Regions:
  • North America
  • Europe
  • Asia Pacific
  • Middle East
  • Latin America
  • Africa
Regulatory Requirements: Some countries require additional documentation:
  • Proof of address
  • Local business registration
  • Government-issued ID
  • Tax ID number
For country-specific requirements, see Twilio Regulatory Guidelines.

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Multiple Phone Numbers

User can add multiple phone numbers: Use Cases:
  • Different regions/countries
  • Different departments
  • Different agents
  • Testing vs production
  • Failover/redundancy
Management:
  • Add unlimited numbers (plan-dependent)
  • Mix types (Callab + SIP + BYOT)
  • Assign different agents to each
  • Track usage per number
  • Set concurrency limits per number

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Assigning Numbers to Agents

User can assign phone numbers to AI agents: Inbound Calls:
  1. Go to Phone Numbers
  2. Edit phone number
  3. Assign to specific agent
  4. Configure call routing
  5. Save configuration
Outbound Calls:
  1. Go to Campaign settings
  2. Select phone number for caller ID
  3. Configure outbound agent
  4. Start campaign

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Phone Number Best Practices

User should:
  • Test with default number first
  • Choose appropriate type for use case
  • Configure proper concurrency limits
  • Monitor call quality and costs
  • Set up backup numbers for critical services
  • Document number assignments
  • Review usage regularly
User should avoid:
  • Using testing numbers for production
  • Exceeding concurrency limits
  • Forgetting to whitelist IPs (SIP trunk)
  • Sharing Twilio Auth Tokens (BYOT)
  • Not testing before deployment

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Next Steps

After adding phone number:
  1. Test your agent - Web call or phone call testing
  2. Setup Inbound Agent - Configure call routing
  3. Setup Outbound Agent - Configure campaigns
  4. Monitor call analytics and quality
Start with Callab Managed numbers for testing. Switch to SIP trunk or BYOT for production if you have existing infrastructure.