Step 1:
Create a new SIP Trunk in 3CX by going to SIP Trunks > Add SIP Trunk.
Country: Generic
Provider: Generic SIP Trunk
Main Trunk Number: (a DID you might have with us)
Step 2: (General Tab)
Registrar: trunking.primevox.net
> Auto-Discovery: YES (required)
Outbound Proxy: trunking.primevox.net
> Auto-Discovery: YES (required)
Type of Authentication: Register / Account Based
Authentication ID: (the SIP Username given to you by a PrimeVOX Technician)
Authentication Password: (the SIP Password given to you by a PrimeVOX Technician)
Step 3: (DIDs / CallerID Tabs)
CallerID/DIDs must have a Country Code. The "+" is not necessary, and not recommended.
Ex. 1) 19726001150
Step 4: (Options Tab)
Re-Register Timeout: 180 Seconds
Transport Protocol: TCP
Step 5: (Outbound Parameters Tab)
"Contact : User Part" = Custom Field (leave the field empty)