Connecting a SIP network with traditional telephony has been a recurring need for our clients. To address this, we developed a new module for our Flexisip server suite in 2023, enabling SIP transmission to traditional telephony. Called Flexisip B2BUA (Back-to-Back User Agent), this component previously only handled outgoing calls from SIP to traditional telephony.We're excited to announce that this limitation will be lifted with the upcoming release of Flexisip (2.4) scheduled for the end of May. We're also conducting extensive work to significantly increase the scalability of this component, aiming for 100,000 users and 30,000 concurrent calls within a few months.

Here are a few examples of use cases:

• For intercom systems: an intercom system connected to an application can dial a phone number as a last resort if the smartphone has no internet access.
• For telecommunication scenarios: a secure enterprise phone network, where internal calls are securely managed byLinphone while still having the capability to call external numbers (without specific security measures).

This enhancement opens up new possibilities by allowing bridging of calls from a domain managed by Flexisip to a third-party domain, and vice versa, at the user level. Essentially, it's now possible to link a user's SIP account with a specific PSTN number. More details can be found in the documentation: SIP Bridge. For organizations not wanting to purchase a PSTN line for each user, it's still possible to configure a fixed number of lines for the B2BUA to draw from during outgoing calls.

Furthermore, this is accompanied by call routing from the Public Switched Telephone Network (PSTN) to the Flexisip server. Communication possibilities are expanded through the connection between the world of traditional telephony and the advanced features offered by the Flexisip server solution.

Stay tuned to learn more about the upcoming features.