Introduction

FreePBX is a GUI for Asterisk, currently maintained by the same company behind Asterisk Sangoma, it's available as a standalone OS based on CentOS, a community made Docker container, or installed next to asterisk on your preffered OS.

Requirements

The requirements are as follow

A Wireguard or other VPN connection to the space
A computer or a VM if you're not containerizing it
a trunk account and extenstion for said trunk
(optional) a SIP phone (available in multiple flavours from the space recommended from the chef is Poly(com) VVX series)
(optional) a Softphone like Linphone,3CXPhone,SimpleSIP etc etc

Demo Setup

At home i run it as follows

A VM on a "server" using the FreePBX OS iso link
Within said OS a Wireguard tunnel to the space link (you might need Google to help you out due it throwing some errors)
A Polycom/Poly VVX400 series phone

Trunks

Found under Connectivity>Trunks

=== General ===
;
; Trunk Name: Custom Name
; Hide CallerID: No
; Outbound CallerID: Example 3011 (Tahtkev)
; CID Options: Allow Any CID
; Maximum Channels: N/A
; Asterisk Trunk Dial Options: System
; Continue if Busy: No
; Disable Trunk: No
; Monitor Trunk Failures: No

Dialed Number Manipulation Rules

We do nothing here we'll manipulate that within Outbound Routes

pjsip Settings

General

Username: "your trunk username"
Auth username: ^
Secret: your trunk password that you've recieved
Authentication: Outbound
Registration: Send
Language Code: English
SIP Server: 10.208.11.13
SIP Server Port: 5060
Context: from-internal
Transport: 0.0.0.0-udp

Advanced

DTMF MODE: RFC4733

Verification that things are working

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus tristique malesuada arcu. Fusce vestibulum ut mauris nec mollis. Quisque lectus dui, ultrices eget arcu ut, porttitor laoreet ipsum. Morbi quam erat, cursus ac dui vel, facilisis consectetur ante. Integer eleifend congue posuere. Fusce augue turpis, luctus sit amet ultrices eget, elementum ut augue. Quisque eu finibus eros. Sed accumsan pretium ultrices. Etiam nec maximus tortor, eu semper risus. Aliquam erat volutpat. Nam pretium ac nisl nec maximus. Vivamus pellentesque euismod volutpat. Phasellus risus purus, vehicula in elementum ut, ultricies a lectus.