Quick answers to common questions about VoxPria SIP trunks, phone numbers, and voice AI integration.
Getting Started #
What are SIP trunks and why do I need them? #
SIP (Session Initiation Protocol) trunks are the connections that allow your AI agents to make and receive phone calls. Think of them as the “phone lines” that connect VoxPria to the telephone network.
Without SIP trunks, your AI agents can only interact via text chat or web interfaces. With SIP trunks, they can:
- Answer incoming phone calls
- Make outbound calls
- Run automated calling campaigns
- Handle customer inquiries by voice
Can I use my existing phone numbers? #
Yes! VoxPria allows you to use phone numbers from any SIP provider. You don’t need to port or transfer your numbers – just import them into VoxPria and connect them to your AI agents.
You can use numbers from:
- Your current SIP provider (Twilio, Telnyx, etc.)
- ElevenLabs (if you use their SIP service)
- Any RFC-compliant SIP provider
Do I need technical expertise to set up SIP trunks? #
No extensive technical knowledge is required! Our setup process is designed to be straightforward:
For ElevenLabs SIP: Just enter your SIP username and password – we handle the rest.
For OpenAI SIP: Provide your Project ID, API key, and webhook secret, and you’re set.
For Generic Providers: You’ll need basic information from your provider (server address, credentials), which they typically provide in their dashboard.
Follow our Quick Start Guide for step-by-step instructions.
How long does setup take? #
Initial setup: 5-10 minutes to create your first trunk and import a number.
Provisioning time:
- ElevenLabs: Usually instant (1-2 seconds)
- OpenAI: Instant after project-level provisioning
- Generic providers: Varies, typically under 30 seconds
Total time to first call: Most users complete setup and receive their first call within 15 minutes.
Choosing a Provider #
Which SIP provider should I choose – ElevenLabs or OpenAI? #
Choose based on your needs:
ElevenLabs SIP – Best for most users:
- ✓ Inbound and outbound calls
- ✓ Voice campaigns
- ✓ All agent types supported
- ✓ Call recordings included
- ✓ Comprehensive features
OpenAI SIP – Choose if you need:
- ✓ GPT-4o Realtime ultra-low latency
- ✓ Advanced AI conversation capabilities
- ⚠ Inbound calls only
- ⚠ No campaigns or recordings
- ⚠ Natural agents only
Recommendation: Start with ElevenLabs for full functionality. Try OpenAI if you specifically need GPT-4o Realtime and only handle inbound calls.
Can I use multiple SIP providers? #
Yes! You can create multiple SIP trunks with different providers. This gives you:
- Redundancy: Backup if one provider has issues
- Cost optimization: Use different providers for different regions
- Feature access: Leverage each provider’s unique capabilities
- Load distribution: Spread call volume across providers
Each phone number is associated with one trunk, but you can have as many trunks as needed.
What if my provider isn’t listed? #
No problem! Select Generic as the provider type and manually enter your provider’s details:
- SIP server address
- Port number
- Transport type (TLS/TCP)
- Authentication credentials
As long as your provider follows standard SIP protocols, it will work with VoxPria.
Can I switch providers later? #
Yes, you can migrate between providers:
- Create a new trunk with different provider
- Import numbers to new trunk
- Test with a few numbers first
- Gradually move remaining numbers
- Delete old trunk when complete
Note: You may need to port numbers between providers if you want to keep the same phone numbers. Check with your providers about porting procedures and fees.
Phone Numbers #
How do I import phone numbers? #
The process is simple:
- Navigate to Phone Numbers in VoxPria
- Click Import Number
- Enter number in E.164 format (e.g.,
+12125551234) - Select your SIP trunk
- Choose engine (ElevenLabs or OpenAI)
- Click Import
See our Quick Start Guide for detailed steps.
What format should phone numbers be in? #
Use E.164 format, which is the international standard:
- ✓ Correct:
+12125551234(+ followed by country code and number) - ✗ Wrong:
2125551234(missing +) - ✗ Wrong:
+1-212-555-1234(has dashes) - ✗ Wrong:
(212) 555-1234(has formatting) - ✗ Wrong:
+1 212 555 1234(has spaces)
Always include: Plus sign (+), country code, and full number with no spaces, dashes, or parentheses.
Can I use toll-free numbers? #
Yes! Toll-free numbers work just like regular numbers. Import them using E.164 format:
- US/Canada:
+18001234567 - UK:
+448001234567
Check with your SIP provider about availability and pricing for toll-free numbers in your region.
How many phone numbers can I have? #
Limits depend on your VoxPria plan:
- Free tier: Typically 1-2 numbers for testing
- Pro tier: Usually 10-50 numbers
- Enterprise: Custom limits based on needs
Contact VoxPria support to discuss increasing limits for your plan.
What happens if I delete a phone number from VoxPria? #
Deleting a number from VoxPria:
- Removes it from your VoxPria account
- Stops AI agent association
- Clears provisioning configuration
Important: This does NOT cancel the number with your SIP provider. You’ll continue paying your provider unless you also cancel with them.
Features and Capabilities #
Can my AI agents make outbound calls? #
Yes with ElevenLabs SIP:
- Agents can make outbound calls
- Use for campaigns or individual calls
- Configure via API or dashboard
No with OpenAI SIP:
- Only inbound calls supported
- No outbound or campaign capabilities
Do I get call recordings? #
ElevenLabs SIP: Yes, all calls are automatically recorded and stored for 90 days. Access them in the Call Logs section.
OpenAI SIP: No server-side recordings due to WebRTC browser-to-browser connections. However, transcripts are available from OpenAI’s API.
If recordings are essential, use ElevenLabs SIP.
Can I run voice campaigns? #
Yes, but only with ElevenLabs SIP phone numbers.
Voice campaigns allow you to:
- Call lists of recipients automatically
- Schedule campaigns for specific times
- Track success rates and metrics
- Retry failed calls
OpenAI SIP does not support campaigns (inbound only).
What agent types work with SIP calls? #
ElevenLabs SIP: All agent types supported
- Natural conversation agents
- Structured workflow agents
- Custom agent configurations
OpenAI SIP: Natural agents only
- Must use conversational approach
- Structured workflows not compatible
Can I transfer calls or use IVR? #
Current VoxPria SIP integration focuses on direct agent-to-caller conversations.
Not currently supported:
- Call transfer to human agents
- Traditional IVR menus
- Conference calling
- Call parking/hold
Supported:
- Direct AI agent conversations
- Custom greetings per number
- Intelligent routing via agent selection
Contact VoxPria for enterprise solutions if you need advanced call routing.
Configuration and Management #
What are “provisions” and why do I need them? #
Provisioning activates a phone number for use with VoxPria. It configures your number with the SIP provider so calls can connect to your AI agents.
ElevenLabs: Each number is provisioned individually
OpenAI: Entire project is provisioned at once
Think of provisioning as “turning on” the phone number for use.
How do I update my SIP credentials? #
- Go to SIP Trunks in VoxPria
- Click Edit on your trunk
- Update username and/or password
- Click Save
- Click Re-provision All Numbers to apply changes
Important: Always re-provision after updating credentials, or calls won’t connect.
Can I use different agents for different numbers? #
Absolutely! Each phone number can have its own assigned agent.
Use cases:
- Sales line with sales agent
- Support line with support agent
- Different languages for different numbers
- Specialized agents for specific services
Configure agent assignments when importing numbers or edit them later.
What’s the difference between TLS and TCP transport? #
TLS (Transport Layer Security):
- ✓ Encrypted connection
- ✓ Secure credentials
- ✓ Recommended for production
- Uses port 5061
TCP (Transmission Control Protocol):
- ⚠ No encryption
- ⚠ Credentials sent in clear
- ⚠ Use only for testing or when TLS unavailable
- Uses port 5060
Recommendation: Always use TLS in production environments for security.
How do I know if my trunk is working? #
Status Indicators:
- Green “Active” status = Working correctly
- Yellow “Provisioning” = In progress
- Red “Failed” = Problem needs attention
Test Methods:
- Make a test call to your number
- Check call appears in Call Logs
- Verify agent answers correctly
- Review audio quality
If status shows “Active” and test calls work, your trunk is configured correctly.
Billing and Costs #
How much does VoxPria charge for SIP calls? #
VoxPria billing:
- SIP trunk feature availability depends on plan
- No per-call charges from VoxPria
- Standard agent usage fees apply (per conversation)
You’ll pay your SIP provider separately for:
- Phone number rental
- Per-minute calling charges
- Any provider-specific fees
What are typical SIP provider costs? #
Approximate costs (varies by provider and region):
Phone Number Rental:
- US local: $1-5/month
- US toll-free: $2-10/month
- International: $2-20/month
Per-Minute Charges:
- Inbound: $0.003-0.015/minute
- Outbound: $0.01-0.05/minute
Check your specific provider’s pricing page for accurate rates.
Are there hidden fees? #
VoxPria: No hidden fees. SIP feature access depends on plan tier.
Your SIP Provider:
- Setup or activation fees (one-time)
- Monthly number rental
- Per-minute usage charges
- Potential overage fees
Always review your SIP provider’s complete pricing structure.
How can I reduce calling costs? #
Cost optimization strategies:
- Choose cost-effective provider – Compare rates (Telnyx often cheaper)
- Use efficient prompts – Shorter conversations = lower costs
- Batch operations – Group calls to avoid multiple sessions
- Monitor usage – Track minutes and optimize high-cost areas
- Negotiate rates – Ask providers for volume discounts
Security and Privacy #
How secure are SIP calls? #
VoxPria implements multiple security layers:
Transport Security:
- TLS encryption for signaling
- SRTP for media encryption (when enabled)
- Secure credential storage
Access Control:
- API key authentication
- Webhook signature verification
- IP allowlisting support (provider dependent)
Best Practice: Always use TLS transport and configure webhook secrets for production.
Are credentials stored securely? #
Yes. SIP trunk credentials are:
- Stored encrypted in the database
- Never exposed in API list responses
- Only returned during creation/update
- Protected by database encryption at rest
For production deployments, ensure your database uses encryption.
What is webhook verification and why is it important? #
Webhook verification authenticates incoming webhook requests using cryptographic signatures.
For OpenAI SIP:
- Webhook secret creates HMAC-SHA256 signature
- Invalid signatures are rejected
- Prevents unauthorized access
Why it matters:
Without webhook verification, anyone knowing your webhook URL could send fake call events, potentially:
- Triggering unauthorized agent interactions
- Accessing sensitive information
- Creating fraudulent usage charges
Always configure webhook secrets for OpenAI SIP.
Can I restrict access by IP address? #
VoxPria Level: Not currently built into the platform.
Provider Level: Many SIP providers support IP allowlisting:
- Restrict origination to specific IPs
- Configure in provider dashboard
- Adds extra security layer
Recommendation: Enable IP allowlisting in your SIP provider settings when available.
Are call recordings private? #
ElevenLabs SIP recordings:
- Stored securely in VoxPria
- Only accessible by your account
- Retained for 90 days (default)
- Can be downloaded and deleted
Compliance: Ensure you follow local laws regarding call recording and consent. Some jurisdictions require informing callers they’re being recorded.
Technical Questions #
What happens if my internet connection fails? #
During a call:
- Call will disconnect if internet drops
- Caller hears standard disconnect message
- Call log shows “failed” status
Prevention:
- Use reliable internet connection
- Consider redundant connections
- Monitor connection quality
- Set up alerts for downtime
After restoration:
- Service resumes automatically
- No manual intervention needed
- New calls connect normally
Can I use VoxPria SIP with my CRM? #
Yes! Integration options:
Via API:
- Use VoxPria API to log calls
- Trigger CRM actions from webhooks
- Sync call data automatically
Via Webhooks:
- Receive real-time call events
- Forward to CRM endpoints
- Update customer records
Zapier/Make:
- Connect VoxPria webhooks to automation platforms
- Route to various CRM systems
- No coding required
See our API Reference for integration details.
Does VoxPria support emergency calling (911)? #
Emergency calling support depends on your SIP provider:
Most Providers (Twilio, Bandwidth, etc.):
- Support E911/emergency calling
- Requires address registration
- Configure in provider dashboard
ElevenLabs/OpenAI:
- Check provider documentation
- May require special setup
Recommendation: Configure emergency calling with your SIP provider for any business-critical phone numbers.
What about international numbers? #
Yes! VoxPria supports international phone numbers:
Requirements:
- Number must be from a supported SIP provider
- Use E.164 format with correct country code
- Provider must support your target country
Examples:
- US:
+12125551234 - UK:
+442012345678 - Australia:
+61212345678 - Japan:
+81312345678
Check with your SIP provider for country availability and pricing.
Can I use VoxPria SIP on mobile networks? #
Yes, but quality depends on connection:
Mobile Data:
- Works over 4G/5G
- Quality varies by signal strength
- May use more data than expected
Recommendations:
- Use WiFi when possible
- Ensure strong signal (3+ bars)
- Test quality before production use
- Consider dedicated circuits for business
Troubleshooting #
My import keeps failing. What do I do? #
Common causes and fixes:
Wrong format: Use E.164 format (+12125551234)
Rate limit: Wait 60 seconds (max 10 imports/minute)
Invalid API key: Check Settings → Integrations
Number doesn’t exist: Verify in provider dashboard
Plan limits: Check if you’ve reached number limit
See our Troubleshooting Guide for detailed solutions.
Calls connect but agent doesn’t respond. Why? #
Check these items:
- Agent assigned? Edit number, verify agent selected
- Agent working? Test in VoxPria web interface first
- System prompt configured? Check agent settings
- For OpenAI: Agent must be “Natural” type
- Check logs: Review call logs for error messages
How do I test my setup without real callers? #
Safe testing methods:
- Use your own phone – Call your VoxPria number
- Test numbers – Some providers offer test numbers
- Small campaign – Run campaign to your own numbers
- Staging trunk – Create separate trunk for testing
- Monitor logs – Check after each test
Best practice: Always test new configurations before going live with customers.
What if my SIP provider isn’t working? #
Troubleshooting steps:
- Check provider status – Visit their status page
- Verify credentials – Ensure username/password correct
- Confirm routing – Check provider’s call routing settings
- Test provider directly – Make test call through provider
- Contact provider – They may need to adjust settings
See Supported SIP Providers for provider-specific guidance.
Advanced Topics #
Can I customize the caller ID for outbound calls? #
ElevenLabs SIP: Yes, the caller ID is the phone number you’re calling from (your VoxPria number).
Custom Caller ID: Depends on your SIP provider’s capabilities. Some providers allow custom caller ID, others require verification.
Legal Note: Many jurisdictions prohibit spoofing caller ID. Ensure compliance with local regulations.
What’s the maximum call duration? #
Default: 1 hour (3600 seconds)
Configurable: Edit phone number settings to change max duration
Provider Limits: Some providers enforce their own limits
Recommendation: Set appropriate limits to prevent excessively long calls and control costs.
Can I use VoxPria SIP for two-factor authentication? #
Yes! VoxPria can handle 2FA voice calls:
Setup:
- Create agent with 2FA prompt template
- Integrate with your authentication system
- Use API to trigger calls
- Verify codes via webhooks
Best for:
- Account verification
- Password resets
- Login confirmations
- Transaction approvals
How do I scale to thousands of calls? #
Scaling considerations:
- Provider capacity – Ensure provider supports volume
- Concurrent limits – Check your plan’s concurrent call limits
- Multiple trunks – Distribute load across trunks
- Infrastructure – Enterprise-grade internet required
- Monitoring – Real-time monitoring essential
Contact VoxPria for enterprise scaling support and architecture guidance.
Getting More Help #
Where can I find more documentation? #
VoxPria Documentation:
- Quick Start Guide – Step-by-step setup
- API Reference – Complete API docs
- Troubleshooting Guide – Problem solutions
- Provider Guides – Provider-specific help
External Resources:
- Provider documentation (Twilio, Telnyx, etc.)
- SIP protocol resources
- VoxPria blog and tutorials
How do I contact support? #
Support Channels:
Email: support@voxpria.com
- Response within 24 hours (business days)
- Attach logs and error messages
- Include account and trunk details
Dashboard: Help → Contact Support
- Built-in ticketing system
- Track support requests
- Direct access to logs
Community: community.voxpria.com
- User forums
- Community knowledge base
- Tips and best practices
Emergency: Mark as “Urgent” priority
- For production outages
- Include impact assessment
- Provide detailed context
Is there a community or forum? #
Yes! Join the VoxPria community:
Community Forum: community.voxpria.com
- Ask questions
- Share experiences
- Learn from other users
- Get tips and tricks
Discord Server: Join for real-time chat
- Quick answers
- Community support
- Product updates
- Networking
Social Media:
- Twitter: @VoxPria
- LinkedIn: VoxPria
- YouTube: VoxPria Tutorials
Can I hire someone to help with setup? #
VoxPria Professional Services:
- Setup assistance
- Configuration consulting
- Custom integrations
- Training and onboarding
Partner Network:
- Certified VoxPria partners
- Implementation specialists
- Ongoing support
Contact sales@voxpria.com for information about professional services and partners.
—
Still Have Questions? #
Can’t find your answer?
- Check our Troubleshooting Guide for specific issues
- Review API Reference for technical details
- Visit Community Forum
- Contact support@voxpria.com
We’re here to help you succeed with VoxPria SIP trunks!
