​

3CX

How to connect your 3CX system with Famulor

​

Create a trunk in 3CX

In the 3CX admin interface, go to “Trunks & Chat” and create a new trunk using +Trunk. Choose “Generic SIP Trunk (IP Based)”.

​

Configure the 3CX trunk

1. Choose any trunk name.
2. Add the number through which Famulor should be reachable internally (you will use a prefix in routing later).
3. Set Registrar to your individual Famulor SIP address.

​

Restrict transport protocol to TCP

​

Required trunk settings

A few non-default settings on the 3CX side are critical for the trunk to work reliably with Famulor:

• Type of Authentication: Do not require - IP based (no SIP REGISTER).
• Disable Registration: ON. Famulor never sends REGISTER — leaving registration enabled produces silent retries and confuses the trunk state.
• Audio Codecs: PCMA, PCMU, plus RFC2833 / telephone-event for DTMF. Disable Opus and G.722 on this trunk — LiveKit’s SIP gateway handles G.711 cleanly, and Opus through 3CX commonly causes one-way audio.
• No SRV record needed. A standard A-record resolution of xxx.sip.livekit.cloud is sufficient.
• Self-hosted 3CX behind NAT: set Public IP + STUN under SBC settings and forward the RTP UDP range (default 9000–10999) — even when signaling uses TCP, RTP is UDP.

​

Optional: Ensure the correct caller number reaches Famulor

If Famulor is used behind a 3CX phone system, the assistant may receive the 3CX system number instead of the real caller number.
To avoid this, set “From: Display-Name” and “Remote-Party-ID” to OriginatorCallerID in the SIP trunk.

​

Create the SIP number in Famulor

After the trunk is set up with your 3CX configuration, you need to import the number into Famulor so we know how to route the call.

1. Open your Famulor.ai Dashboard
2. Navigate to Phone Numbers
3. Click on “Integrate SIP trunk”
   
4. Enter your details according to your 3CX configuration:
   Number / Name: Use exactly the same number as in your 3CX configuration (e.g., +49 151 12345678).
   Termination URL: The address of your 3CX system, if you want to make outbound calls.
   Username: Leave blank if no username was configured.
   Password: Leave blank if no password was configured.
   
   

If the number is already taken, choose another one.

​

Create an outbound rule in 3CX

Now create an outbound rule that defines when this trunk should be used.
For example, you can use 999 as a prefix; just make sure those digits are stripped before dialing. Important: Place this outbound rule above other rules that could otherwise override it.

​

Inbound DID routing

To make an external call to a 3CX-hosted DID actually reach Famulor, route the DID through the outbound trunk you just created. In 3CX:

1. Go to the DID’s Inbound Rule (or the user/queue that owns the DID).
2. Set “Office Hours” and “Out of Office” routing destinations to “External” with the dial string 999<your-famulor-number> (using the prefix from the outbound rule above).
3. The outbound rule strips the 999 prefix and sends the call to Famulor.

This is what actually closes the loop — without it, the outbound rule exists but no inbound traffic ever uses it.

​

Outbound from Famulor → 3CX

When Famulor places an outbound call (for example a Make-phone-calls assistant), it talks to your 3CX trunk over the same SIP host. Make sure 3CX accepts those INVITEs:

• Either add Famulor’s current SIP egress IP ranges to the trunk’s allow-list (request the list from Famulor support), or
• Provision Digest credentials on the 3CX side and enter them in Famulor’s Username / Password fields when importing the number.

​

Using the number

You can now use this number, for example, in absence routing or other 3CX routing rules.