Connect Telnyx SIP trunk to SessionPBX

Telnyx supplies phone numbers in many countries, including the UK and US, and outbound calling over SIP connections. SessionPBX has a Telnyx template, and can read your Telnyx account to fill in your numbers and connection details.

You bring your own Telnyx account, numbers and caller ID. SessionPBX doesn’t supply Telnyx service.

About this guide. The Telnyx settings on this page were checked against Telnyx’s published documentation on 19 October 2026. The SessionPBX field names come from the Add SIP trunk wizard in the product. If Telnyx shows a different value in your account, use theirs.

Before you start

In Telnyx Mission Control:

1. Open Voice > SIP Trunking and create a SIP connection with IP address authentication (or FQDN). This is the recommended setup for SessionPBX.
2. On the connection, enter your SessionPBX region’s hostname or IP address from the table below as the inbound destination. Choose the inbound SIP region nearest you, set the inbound transport to UDP or TLS, not TCP, and leave SRTP off.
3. For outbound calls, add your SessionPBX region’s IP address from the table below to the connection’s allowed IP addresses.
4. Assign your numbers to the connection.
5. Create an Outbound Voice Profile, add the connection to it, and allow every country you’ll call. For UK calls, the profile must include the United Kingdom.
6. To let SessionPBX read your account, create an API key under API Keys. This is optional.

Username and password (credentials) connections aren’t supported yet. SessionPBX can’t yet place outbound calls over a Telnyx credentials connection, so use IP authentication as described on this page. Credential support is coming soon.

With IP authentication, Telnyx recognises your calls by your SessionPBX region’s IP address. Every workspace in a region sends calls from the same address. Whether Telnyx lets more than one account allow the same address is still being confirmed. If Telnyx says the address is already in use on another account, email support@sessiontalk.co.uk.

Telnyx’s regional SIP proxies are:

Telnyx accepts UDP or TCP on port 5060 and TLS on port 5061. Use the region nearest your SessionPBX region: Europe for London, US for New York.

Add the trunk in SessionPBX

1. Open the SessionPBX project and select Call Routing.
2. On SIP trunks, select Add trunk.
3. Provider: name the trunk and choose Telnyx. To read your account, enter your key in API key (V2) under Connect your Telnyx account and select Connect account. SessionPBX lists your numbers, and fills in the SIP host and transport from your connection where Telnyx provides them.
4. Connection: the template fills in sip.telnyx.com, port 5060 and UDP. If your workspace is in London, you can change Host to sip.telnyx.eu. Leave Direction on Both directions.
5. Authentication: the Telnyx template starts on Username and password. Change it to By our IP address, and list both signalling IPs for your Telnyx region under Carrier IP addresses, for example 185.246.41.140 and 185.246.41.141 for Europe. Use the signalling IPs from Telnyx’s SIP information page. Telnyx’s webhook addresses are a different set, and using them blocks every incoming call.
6. Inbound: your numbers are listed if you connected the account. Otherwise enter them one per line in international format, for example +442071234567.
7. Outbound: set Caller ID to a number on this Telnyx account.
8. Select Create trunk.

SessionPBX addresses for Telnyx

Give Telnyx the address for the region your workspace is hosted in. If you’re not sure which region that is, email support@sessiontalk.co.uk.

SessionPBX accepts calls from carriers on UDP port 5060 or TLS port 5061. TCP isn’t accepted for incoming calls. Calls that SessionPBX sends to Telnyx can use UDP, TCP or TLS on whatever port Telnyx specifies.

Route your numbers

On Call Routing, use Inbound number routing to choose where each number rings: everyone, a team member, a ring group, a call queue or a call flow. See Phone Numbers & Outbound Calls.

Allow members to call out

Outbound calling is off for new members. Open Team Members, edit the member, turn on Outbound PSTN under Access & features, and select Save member.

Members can dial numbers in international format, such as +447700900123. SessionPBX sends the number to Telnyx in international format.

Test the trunk

1. Call one of your Telnyx numbers from an outside phone and check that the right destination rings.
2. With Outbound PSTN on for one member, call a public number. Check that audio works both ways and that the called phone shows the caller ID you expect.
3. If you call into an IVR, check that key presses work. SessionPBX sends and receives key presses as RFC 2833 telephone events.

If calls fail, email support@sessiontalk.co.uk with the time of the call, the number you called from and the number you called.

Sources

• Telnyx: SIP information (regions, IPs, ports, codecs) 
• Telnyx: How to configure a SIP trunk