Set up an SMS Channel for Telnyx

This topic describes how to set up a Telnyx SMS channel on Yeastar P-Series PBX System, so that agents in your business can receive and reply to SMS messages from customers on their Linkus UC Clients.


The Yeastar PBX should meet the following requirements:

  • Firmware: Version or later
  • Plan: Enterprise Plan (EP) or Ultimate Plan (UP)
  • FQDN: PBX can be accessed via Yeastar FQDN.
    Note: Due to the limitation of the third-party platform, the FQDN domain name must NOT contain underscore character(s), otherwise the messaging channel will encounter authentication failure, or will fail to receive messages.

    For more information about the configuration, see Configure Network for Remote Access by a Yeastar FQDN.

Supported message types and limits

Supported message types
The Telnyx SMS channel supports text messages and multimedia messages (MMS), where the supported MMS file types are determined by Telnyx. For more information, see Telnyx supported MMS file types.
Important: When sending multimedia messages (such as images), the SMS service provider downloads the files from a link provided by the PBX. Therefore, if you have set Allowed Country/Region IP Access Protection rule, make sure that you have allowed the IP access from the country where the SMS service provider is located, otherwise the file transmission would fail.
  • File size: Max. 100 MB
  • File retention period: 24 hours


Step 1. Obtain a Webhook URL on PBX

Obtain a Webhook URL from PBX web portal first, which is required when you configure a number for SMS on Telnyx.

  1. Log in to PBX web portal, go to Messaging > Messaging Channel.
  2. Click Add, and select SMS.
  3. In the ITSP drop-down list, select Telnyx.

    A Webhook URL for Telnyx is generated and displayed in the Webhook URL field.

    Important: The URL will change once you leave the current page, please make sure you use the latest Webhook URL for the configuration on the service provider's customer portal.

  4. Note down the Webhook URL.

Step 2. Configure a number for SMS on Telnyx

Important: According to US legislation (A2P 10DLC SMS), 10DLC (10-digit Long Code) phone numbers that are used for A2P (Application-to-Person) messaging MUST be registered, otherwise SMS messages sent to US numbers from the unregistered 10DLC numbers will be blocked.

If your business communicates with US-based customers, you should confirm the registration requirements with the SMS service provider and complete the phone number registration to avoid disruption in message delivery.

Log in to Telnyx portal, and complete the following settings:

  1. Search and purchase a DID number with SMS feature.

  2. Create a message profile and configure messaging webhook with PBX's Webhook URL.

  3. Assign the message profile to the purchased DID number.

  4. Create an API key for the integration with PBX.

  5. Note down the API key in API Key tab, and the Public key in Public Key tab.

Step 3. Create and configure an SMS channel on PBX

  1. Log in to PBX web portal, go to Messaging > Messaging Channel.
  2. Click Add, and select SMS.
  3. In the Authentication tab, enter the authentication information of Telnyx.

  4. In the Messaging Settings tab, configure the channel.
    1. In the Message Sending Rate drop-down list, specify the number of messages that PBX can send per second.
      • If the number of messages to send exceeds the set value, PBX will arrange the messages in queue and send them at the sending rate.
      • If the sending rate set in PBX exceeds the limit set by the SMS service provider, it may result in message delivery failures. Contact your SMS service provider to confirm the sending rate limit of your account and increase the limit as needed.
    2. Optional: If you want the system to automatically close the sessions that have been inactive for a specific period of time, select the checkbox of Close Session Automatically, then set the timeout in the Session Timeout (Days) field.

    3. In the Number section, click Add to add a message routing rule.

      • Number: Enter the purchased number in E.164 format ([+][country code][phone number]). For example, +14102161183.
      • Destination for Inbound Messaging: Specify the destination of inbound messages from the number.
        Option Description
        Extension If selected, choose an extension from the Extension drop-down list.

        Only the extension user can receive inbound messages from the number.

        Message Queue If selected, choose a queue from the Message Queue drop-down list.

        All the agents in the selected message queue can receive inbound message(s) of new sessions in the queue. However, only the user who picks up a session will be able to receive and respond to the follow-up inbound messages in the session.

      • Extensions allowed to create messaging sessions: Select the extensions that are allowed to initiate a messaging session with customers.
    4. Click Save.
  5. Click Save.


  • A messaging channel is created successfully. You can see the channel displayed in the Messaging Channel list with Status showing .

  • PBX automatically tracks and records the number of messages sent and received on the channel, where the Total column indicates the total number of sent messages, including both successfully sent messages and failed ones.
    • For sent messages, PBX only tracks the number of the messages sent from agents' Linkus UC Clients. If you want to calculate the actual cost of sent messages, consult with the SMS service provider for the precise number of messages transmitted, as long text messages (longer than 160 characters) are automatically split into segments and then re-assembled when they are received, increasing the number of sent messages.
    • You can filter the statistics by a time period using the time filter.

What to do next

Send text messages to the phone number and see if the specified agent can receive messages on his or her Linkus UC Client.