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Telnyx Calling: SIP Trunking — Documentation Index

SIP Trunking documentation within the Calling section of the Telnyx developer docs (https://developers.telnyx.com). This file: https://developers.telnyx.com/docs/development/llms/calling-sip-trunking-llms-txt.md · Root index: https://developers.telnyx.com/llms.txt

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Getting Started

• Overview: Overview of Telnyx SIP Trunking — buy numbers, create a SIP connection, configure authentication and routing, and place your first inbound/outbound call.

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Authentication

• Overview: SIP authentication methods supported by Telnyx SIP Trunking — credential, IP, FQDN, and token authentication. Compare and choose the right method.
• IP Authentication Token: Use IP authentication tokens on Telnyx SIP Trunking to authenticate calls without a fixed allowlist. Generate tokens and include them in SIP INVITEs.
• Tech Prefix: Authenticate Telnyx SIP Trunking calls with a tech prefix. Prepend a numeric prefix to the request URI to identify your account on outbound INVITEs.

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Configuration

• Caller ID Policy: Configure caller ID policy on Telnyx SIP Trunking connections. Allow, override, or block From and P-Asserted-Identity values on outbound calls.
• Concurrent Call Limits: Set concurrent call limits on Telnyx SIP Trunking connections. Cap inbound and outbound channels per connection to protect capacity and control spend.
• P-Charge-Info: Use the P-Charge-Info SIP header on Telnyx SIP Trunking to specify the billed number for outbound calls. Includes header format and behavior rules.
• Outbound Voice Profiles for SIP trunking: Attach Outbound Voice Profiles to Telnyx SIP Trunking connections to control allowed destinations, rate limits, daily spend, and outbound routing.

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Routing

• Round Robin Routing: Distribute Telnyx SIP Trunking traffic evenly across multiple destinations using round-robin routing. Spread load between PBXes or geographic regions.
• AnchorSite: Configure AnchorSite to control which Telnyx PoP handles media routing for SIP calls, with latency-based and manual selection modes.
• Failover & Retries: Configure failover and retry behavior on Telnyx SIP Trunking. Route calls to backup destinations on SIP failure codes for high availability.

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Network Configuration

• IP Whitelisting: Whitelist your IP addresses on Telnyx SIP Trunking connections to authenticate calls without credentials. Includes allowed CIDR ranges, edge IPs, and AI services IPs.
• SRV Records: Use SRV records to route SIP traffic to Telnyx with automatic failover. Configure DNS for sip._udp / sip._tcp and let your PBX resolve Telnyx edges.
• STUN/TURN: Connect WebRTC and NAT-traversed SIP clients to Telnyx using STUN and TURN servers. Includes hostnames, ports, and authentication for media relays.

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Features

• Noise Suppression: Enable AI noise suppression on Telnyx SIP Trunking calls. Remove background noise from inbound or outbound audio for clearer phone conversations.
• Jitter Buffer: Configure the adaptive jitter buffer on Telnyx SIP Trunking to smooth out RTP packet delay and improve voice quality on lossy or variable networks.
• External Transfers: Use SIP REFER to transfer Telnyx SIP Trunking calls to external numbers. Configure your PBX or Voice API to hand off calls without bridging media.
• SIP URI Calling: Place and receive SIP URI calls over Telnyx SIP Trunking. Dial endpoints by sip:user@domain instead of E.164 to connect VoIP systems directly.

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STIR/SHAKEN

• Attestation Behavior: How Telnyx assigns STIR/SHAKEN attestation levels (A, B, C) to outbound calls. Understand the criteria, signed identity headers, and downstream impact.
• Hosted Certificate: Use a Telnyx hosted STIR/SHAKEN certificate to sign outbound calls without managing your own CA. Includes setup, certificate rotation, and verification.
• SIP Header Parameters: Reference of STIR/SHAKEN SIP header parameters used by Telnyx — Identity, attest, origid, dest, and how to read and verify a signed identity header.

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Emergency Calling

• Dynamic E911: Provision Dynamic E911 on Telnyx SIP Trunking for VoIP emergency calling. Register caller locations dynamically and route 911 calls to the correct PSAP.

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Troubleshooting

• Response Codes: Reference of SIP response codes you’ll see on Telnyx SIP Trunking calls — 4xx client errors, 5xx server errors, 6xx global failures, and what they mean.

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SIP Integrations Guides

• Configuration Overview: Telnyx’s SIP trunking guide will help you configure your sip
• LiveKit: Integrate Telnyx SIP Trunks with LiveKit for real-time audio and video applications. Includes Telnyx configuration and LiveKit SIP gateway setup steps.

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API Reference (SIP Trunking)

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Connections

• List connections: Returns a list of your connections irrespective of type.
• Retrieve a connection: Retrieves the high-level details of an existing connection. To retrieve specific authentication information, use the endpoint for the specific connection type.

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Credential Connections

• List credential connections: Returns a list of your credential connections.
• Create a credential connection: Creates a credential connection.
• Delete a credential connection: Deletes an existing credential connection.
• Retrieve a credential connection: Retrieves the details of an existing credential connection.
• Update a credential connection: Updates settings of an existing credential connection.
• Check a Credential Connection Registration Status: Checks the registration_status for a credential connection, (registration_status) as well as the timestamp for the last SIP registration event (`registration…

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IPs

• List Ips: Get all IPs belonging to the user that match the given filters.
• Create an Ip: Create a new IP object.
• Delete an Ip: Delete an IP.
• Retrieve an Ip: Return the details regarding a specific IP.
• Update an Ip: Update the details of a specific IP.

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IP Connections

• List Ip connections: Returns a list of your IP connections.
• Create an Ip connection: Creates an IP connection.
• Delete an Ip connection: Deletes an existing IP connection.
• Retrieve an Ip connection: Retrieves the details of an existing ip connection.
• Update an Ip connection: Updates settings of an existing IP connection.

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FQDNs

• List FQDNs: Get all FQDNs belonging to the user that match the given filters.
• Create an FQDN: Create a new FQDN object.
• Delete an FQDN: Delete an FQDN.
• Retrieve an FQDN: Return the details regarding a specific FQDN.
• Update an FQDN: Update the details of a specific FQDN.

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FQDN Connections

• List FQDN connections: Returns a list of your FQDN connections.
• Create an FQDN connection: Creates a FQDN connection.
• Delete an FQDN connection: Deletes an FQDN connection.
• Retrieve an FQDN connection: Retrieves the details of an existing FQDN connection.
• Update an FQDN connection: Updates settings of an existing FQDN connection.
• Retrieve an FQDN authentication: Retrieves the details of an existing FQDN authentication strategy for a specific FQDN connection.
• Update an FQDN authentication: Updates the FQDN authentication strategy for a specific FQDN connection.

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UAC Connections

• List UAC connections: Returns a list of your UAC connections. A UAC (User Agent Client) Connection registers Telnyx to your PBX — the opposite of a standard SIP trunk, where the PBX…
• Create a UAC connection: Creates a UAC connection. A UAC (User Agent Client) Connection registers Telnyx to your PBX — the opposite of a standard SIP trunk, where the PBX registers to…
• Delete a UAC connection: Deletes an existing UAC connection.
• Retrieve a UAC connection: Retrieves the details of an existing UAC connection.
• Update a UAC connection: Updates settings of an existing UAC connection.
• SIP Registration Status: Returns the live SIP registration status for a Telnyx endpoint: whether it is currently registered, when the current registration expires, and the last respons…

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Outbound Voice Profiles

• Get all outbound voice profiles: Get all outbound voice profiles belonging to the user that match the given filters.
• Create an outbound voice profile: Create an outbound voice profile.
• Delete an outbound voice profile: Deletes an existing outbound voice profile.
• Retrieve an outbound voice profile: Retrieves the details of an existing outbound voice profile.
• Updates an existing outbound voice profile.: Updates an existing outbound voice profile.

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Dialogflow Integration

• Delete stored Dialogflow Connection: Deletes a stored Dialogflow Connection.
• Retrieve stored Dialogflow Connection: Return details of the Dialogflow connection associated with the given CallControl connection.
• Create a Dialogflow Connection: Save Dialogflow Credentiails to Telnyx, so it can be used with other Telnyx services.
• Update stored Dialogflow Connection: Updates a stored Dialogflow Connection.

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External Connections

• List all External Connections: This endpoint returns a list of your External Connections inside the ‘data’ attribute of the response. External Connections are used by Telnyx customers to sea…
• Creates an External Connection: Creates a new External Connection based on the parameters sent in the request. The external_sip_connection and outbound voice profile id are required. Once cre…
• Deletes an External Connection: Permanently deletes an External Connection. Deletion may be prevented if the application is in use by phone numbers, is active, or if it is an Operator Connect…
• Retrieve an External Connection: Return the details of an existing External Connection inside the ‘data’ attribute of the response.
• Update an External Connection: Updates settings of an existing External Connection based on the parameters of the request.
• List all civic addresses and locations: Returns the civic addresses and locations from Microsoft Teams.
• Retrieve a Civic Address: Return the details of an existing Civic Address with its Locations inside the ‘data’ attribute of the response.
• Update a location’s static emergency address: Update the static emergency address assigned to a specific location of an external connection.
• List all phone numbers: Returns a list of all active phone numbers associated with the given external connection.
• Retrieve a phone number: Return the details of a phone number associated with the given external connection.
• Update a phone number: Asynchronously update settings of the phone number associated with the given external connection.
• List all Releases: Returns a list of your Releases for the given external connection. These are automatically created when you change the connection_id of a phone number that i…
• Retrieve a Release request: Return the details of a Release request and its phone numbers.
• List all Upload requests: Returns a list of your Upload requests for the given external connection.
• Creates an Upload request: Creates a new Upload request to Microsoft teams with the included phone numbers. Only one of civic_address_id or location_id must be provided, not both. The ma…
• Refresh the status of all Upload requests: Forces a recheck of the status of all pending Upload requests for the given external connection in the background.
• Get the count of pending upload requests: Returns the count of all pending upload requests for the given external connection.
• Retrieve an Upload request: Return the details of an Upload request and its phone numbers.
• Retry an Upload request: If there were any errors during the upload process, this endpoint will retry the upload request. In some cases this will reattempt the existing upload request,…
• List all log messages: Retrieve a list of log messages for all external connections associated with your account.
• Dismiss a log message: Dismiss a log message for an external connection associated with your account.
• Retrieve a log message: Retrieve a log message for an external connection associated with your account.
• Refresh Operator Connect integration: This endpoint will make an asynchronous request to refresh the Operator Connect integration with Microsoft Teams for the current user. This will create new ext…

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Call Recordings

• List all call recordings: Returns a list of your call recordings.
• Delete a call recording: Permanently deletes a call recording.
• Retrieve a call recording: Retrieves the details of an existing call recording.
• Delete a list of call recordings: Permanently deletes a list of call recordings.
• List all recording transcriptions: Returns a list of your recording transcriptions.
• Delete a recording transcription: Permanently deletes a recording transcription.
• Retrieve a recording transcription: Retrieves the details of an existing recording transcription.
• Delete a stored credential: Deletes a stored custom credentials configuration.
• Retrieve a stored credential: Returns the information about custom storage credentials.
• Create a custom storage credential: Creates a custom storage credentials configuration.
• Update a stored credential: Updates a stored custom credentials configuration.

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Media Storage API

• List uploaded media: Returns a list of stored media files.
• Upload media: Upload media file to Telnyx so it can be used with other Telnyx services
• Deletes stored media: Deletes a stored media file.
• Retrieve stored media: Returns the information about a stored media file.
• Update stored media: Updates a stored media file.
• Download stored media: Downloads a stored media file.