PBX · 3CX v18 / v20

Set up a SIP trunk in 3CX with DIDHub

3CX recognizes DIDHub via the generic SIP trunk template. This tutorial walks through the field values, DID inbound mapping, and outbound rule.

Step 1: Add the trunk

3CX Console → SIP Trunks → Add SIP Trunk.

Field	Value
Country	Generic
Provider	Generic SIP Trunk
Main Trunk No.	+15551234567
Registrar / Server	sip.didhub.io
Type of authentication	Register / Account based
Authentication ID	trunk_xxxxx
Authentication password	<from DIDHub>
3 simultaneous calls	(based on plan)
SBC Required	No

Step 2: DID rule (inbound)

Trunk detail → DIDs tab → Add DID: +15551234567 → Destination: Extension 100 (or queue, or IVR).

Step 3: Outbound rule

Outbound Rules → Add
Name              : DIDHub-Outbound
Calls to numbers starting with : +
Make outbound calls on    : DIDHub
Strip digits      : 0
Prepend           : ""  (already E.164)

Step 4: Codec order

Trunk detail → Options tab → reorder codecs: ulaw, alaw, opus. Disable G.722 for compatibility.

Step 5: Test

• Inbound: dial +1 555 123 4567 from any phone — Ext 100 should ring.
• Outbound: from Ext 100 dial +1 555 765 4321.
• Trunk status: green dot in the SIP Trunks list = registered.

Tips

• 3CX v20 supports OPUS — enable it for better quality on mobile clients.
• For Hosted 3CX, the public IP for ACL is shown in Dashboard → Information. Pin it on the DIDHub trunk if using IP-ACL mode.