Connect your 3CX PBX to IllyVoIP for outbound calling and incoming DID calls. This walkthrough covers the SIP trunk, outbound rule and incoming-number routing. Menu names and generic-trunk availability depend on your 3CX version and edition.
Step 1: Prepare your IllyVoIP account
Sign in and open Services → SIP Lines. Select the identity intended for your PBX. Note its authentication mode, SIP username, regional server, transport and call-audio setting. Keep the SIP password private and do not use the Portal login password.
Check your selected routing package, allowed Caller ID and available balance. For incoming calls you also need an active phone number and a saved route to your PBX.
Step 2: Open the 3CX administrator interface
Use your own 3CX administrator account. In versions with the Voice & Chat menu, open it and choose the option to add a SIP trunk. Other versions label this section SIP Trunks. Use a generic configuration when supported by your installation; do not select an unrelated carrier template simply because it appears in an old screenshot.
Step 3: Configure the SIP trunk
- Name: choose a descriptive name such as IllyVoIP.
- Registrar/server: copy the server shown for your selected IllyVoIP line and region.
- Authentication ID: use your SIP username for password authentication.
- Authentication password: use that line's SIP password, not your 3CX or Portal password.
- IP authentication: if using this mode, first configure the PBX's public source IP on the intended IllyVoIP SIP line. Do not mix an unrelated username/password configuration with IP authentication.
- Transport and audio: match the supported settings on both sides. A signaling connection alone does not prove that audio encryption and media settings match.
Save the trunk and check its status. For version-specific fields and supported configurations, consult the 3CX SIP-trunk guide. A generic configuration is not a claim that IllyVoIP is a 3CX-certified provider.
Step 4: Create an outbound rule
In 3CX Outbound Rules, create a rule for the extensions and numbers you want to route through IllyVoIP. Select the IllyVoIP trunk. Check the digits after any strip/prepend operation: the destination must be in the international format expected by your route.
If using a package technical prefix, copy its current value from IllyVoIP and apply it only once. Do not reuse a historical prefix from a screenshot. Use a Caller ID permitted by your account and selected package. See the 3CX outbound-routing guide for version-specific rule matching.
Step 5: Add your incoming DID numbers
Add each active IllyVoIP DID to the trunk's DID list. Use the incoming-number format expected by your 3CX configuration. Then assign the number to an extension, ring group or other intended destination in 3CX.
Step 6: Route the number from IllyVoIP
Open Phone Numbers, choose the active DID and select Configure. Save the supported route to your PBX or the appropriate registered SIP identity. External-SIP routing and registration are different delivery choices: configure the one you intend to use, with the correct region and network access.
Step 7: Test both directions
- Make an outbound call from an allowed 3CX extension to a number you control.
- Confirm ringing, answer, audio in both directions and the Caller ID seen by the recipient.
- Call your DID from another phone and confirm the intended 3CX destination rings.
- Review both the 3CX event log and IllyVoIP Call Reports if a test fails. Send support the public call reference and symptoms, never passwords.
Original vendor illustrations are retained where relevant; private values are obscured and should not be copied. Configure your own numbers and credentials.