Learning Hub / Tutorials / 3CX / SIP Trunk Setup (V20)FAQs

Tutorials: SIP Trunk Setup (V20)

Learn how to set up a Voxtelesys SIP Trunk in 3CX Version 20! Keywords: 3CX, V20, SIP Trunk, Admin

Required Access: 3CX


Last Updated: 5/21/2025

3cx login



Enter your credentials.

admin button



Click on the "Admin" button on the lower left side of the screen.

voice & chat tab in 3CX



Select the "Voice & Chat" tab.

add sip trunk button



Select the "+ Add SIP Trunk" button, then click on "Add Trunk" from the drop-down menu.

general sip trunk settings

Get the SIP Trunk’s information (retrieve it from the Voxtelesys Portal):

  • Name: Choose your name for the trunk
  • Country: US
  • Trunk: Voxtelesys

general settings

Make sure that the following:

  • Registrar/Server: Confirm it shows 3cx.pstn.voxtelesys.net
  • Auto Discovery: Make sure the first Auto discovery is checked.
  • Outbound Proxy: Make sure outbound proxy is blank.
  • Port: Set port behind outbound proxy to 5060 if not prefilled.
  • Second Auto Discovery: Make sure second auto discovery is unchecked.
sip trunk settings in 3cx

Enter the following:

  • Main trunk number: Fill in the Voxtelesys SIP Trunk number in the E164 format.
  • Authentication ID (SIP User ID): From Voxtelesys
  • Authentication password: From Voxtelesys
default outbound caller id

Default Outbound Caller ID:

Set the number in the E164 format as the example shows.

did numbers under add trunk in 3CX

Optional - Add or import more DID numbers here:

sms tab under add trunk in 3CX



Optional - Check Enable SMS here:

verified trunk in 3CX



Save and verify that the Voxtelesys SIP Trunk registered.

Learning Hub / Tutorials / 3CX / SIP Trunk Setup (V20)FAQs