FreeSWITCH: Credentials Trunk

Here we will explain how to configure a FreeSWITCH Credentials Trunk with Telnyx.

Dillin avatar
Written by Dillin
Updated over a week ago

FreeSWITCH™ is a scalable open source cross-platform telephony suite designed to route and interconnect popular communication protocols using audio, video, text or any other form of media. From a Raspberry PI to a multi-core server, FreeSWITCH can unlock the telecommunications potential of any device.

FreeSWITCH also provides a stable telephony platform on which many telephony applications can be developed using a wide range of free tools.

Additional documentation:

  • Get in touch with FreeSWITCH here

  • Check out their help section for community or paid support.

Instructions For Configuring a FreeSWITCH IP Trunk

In this guide, you will:


IMPORTANT: FreeSWITCH™ v1.8 has been tagged End of Life. If you are on this version, you must upgrade.

1. Extension configuration for registering a SIP phone

You may register to one of the existing extensions; however it is recommended that you change the default password in the directory/default/1000.xml file:

<param name="password" value="abcd1234"/>
<!-- Replace abcd1234 with a strong password -->

2. Create the SIP trunk

Create a file under directory: sip_profiles/external (i.e.: sip_profiles/external/telnyx.xml)

Note: If you have a linksys device (spa2102 spa5xx series), they will reject calls if ptime is not set to 20. Make sure you change that in the phone's configuration (rtp packet size 0.020 [from 0.030]) i.e.: sip_profiles/external/telnyx.xml - telnyx.xml should contain the following:

<gateway name="telnyx">
<param name="realm" value=""/>
<param name="username" value="freesuser"/>
<!-- Replace freesuser with your Telnyx Portal username -->
<param name="password" value="freespass"/>
<!-- Replace freepass with your Telnyx Portal password -->
<param name="register" value="true"/>

3. Create a dialplan

File to edit: dialplan/default.xml - add the following to default.xml

<extension name="dial">
        <condition field="destination_number" expression="^(1{0,1}\d{10})$">
        <action application="set" data="effective_caller_id_number=13125489677"/>
        <!-- Replace 3125489677 with the DID you want as CID -->
        <action application="bridge" data="sofia/gateway/telnyx/$1"/>

4. Create an inbound trunk - DID

Create a file under directory: dialplan/public/

ie. dialplan/public/3125489677.xml - 3125489677.xml is the DID you purchased at Telnyx Mission Control Portal and should contain the following:

    <extension name="public_did">
        <condition field="destination_number" expression="^(13125489677)$">
        <!-- Replace 13125489677 with the DID you purchased at the Telnyx Portal -->
            <action application="set" data="domain_name=$${domain}"/>
            <action application="transfer" data="1000 XML default"/>

5. Configure your network

If you want to use the same profile for communication both inside and outside your network, you will need to tell FreeSWITCH™ when it should use the local IP or the external IP.

The autonat: prefix toggles on the usage of the local-network-acl, if you prefix the IP like that it will activate the dynamic ability to tell when it should use ext-rtp-ip vs rtp-ip based on the acl match.

<param name="ext-sip-ip" value="autonat:$${external_sip_ip}"/>

Note: In case FreeSWITCH fails to recognize your public IP you may "force" it to use a static Public IP by modifying sip_profiles/external.xml as follows:

<param name="ext-rtp-ip" value=""/>
<param name="ext-sip-ip" value=""/>
<!-- Replace with your public IP -->

Additional Resources

Review our getting started with guide to make sure your Telnyx Mission Control Portal account is setup correctly!

Additionally you can:

  • Get in touch with FreeSWITCH here

  • Check out their help section for community or paid support.

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