SIP Trunk Setup for Synthflow.ai
Use Voyced as an external SIP provider
What You’ll Need
Before you begin, make sure you have:
- Access to your Synthflow.ai dashboard
- An active Synthflow agent / flow
- Your Voyced SIP details:
- Account / telephone number:
Your-Voyced-DID - Service password:
YourServicePassword - SIP server:
sip.voyced.eu
- Account / telephone number:
Requirements Before You Begin
- Synthflow must support SIP trunk registration (not just URI forwarding)
- SIP transport must use UDP (port 5060)
- Disable SIP ALG on your firewall/router
- Ensure outbound access to
sip.voyced.eu - Enable codecs:
- PCMA (alaw)
- PCMU (ulaw)
SIP Trunk Setup Steps
1. Open SIP Settings in Synthflow
- Log in to Synthflow.ai
- Open your Agent / Flow
- Go to Phone System / SIP Configuration
2. Create a New SIP Connection
Add a new SIP trunk or external connection and enter:
| Field | Value |
|---|---|
| SIP Server / Host | sip.voyced.eu |
| Port | 5060 |
| Transport | UDP |
| Username | Your-Voyced-DID |
| Password | YourServicePassword |
| Auth ID | Your-Voyced-DID |
| From User | Your-Voyced-DID |
| From Domain | sip.voyced.eu |
3. Enable Registration
- Set Registration to Enabled
- Registration interval: 3600 seconds
Save the configuration.
4. Codec Configuration
Set codec priority to:
- PCMA (alaw)
- PCMU (ulaw)
Disable unused codecs to avoid negotiation issues.
5. Assign Number / DID
-
Link your Synthflow agent to:
Your-Voyced-DID - Ensure inbound calls to this DID are accepted by the SIP trunk
Testing Your Setup
- Check trunk status → should show Registered
- Call your Voyced number from a mobile
- Confirm:
- Call reaches Synthflow
- Agent answers
- Audio works both ways
Troubleshooting
- Not registering
- Check username/password
- Verify firewall allows UDP 5060
- 403 / 401 errors
- Authentication mismatch
- 404 errors
- DID not correctly mapped in Synthflow
- One-way audio
- RTP ports blocked or NAT issue
Final Tips
- Always use:
Your-Voyced-DIDas username and From User
- Keep From Domain = sip.voyced.eu
- Avoid any SIP URI forwarding setups
- Keep configuration simple and registration-based
Last updated: 08/04/2026
© Voyced
All information provided is copyrighted and purely informative in nature. It is maintained by Voyced with the greatest of care using reliable sources only.
Given the fast evolution of the telecom sector, Voyced does not offer any guarantee about the accuracy and completeness of the information offered.
We explicitly do not give anyone permission to use this information in any other way than to inform themselves about what (legal) requirements there may be and they need to comply with when registering Services and/or DIDs with Voyced.
