What are the benefits of switching to a SIP trunk service from ISDN?

The move from ISDN to SIP trunking is a key step in preparing for the BT PSTN switch-off, scheduled for January 2027. As traditional telephony infrastructure is phased out, organisations must transition to IP-based services to maintain voice communications.

Cinos experts Jono Darlington and Richard Evans explore the key benefits of moving to SIP — particularly for critical calling environments — in the following blog articles:

In summary, switching to SIP delivers a range of benefits for organisations of all types, including:

  • Futureproofing: Ensures your organisation is ready ahead of the PSTN switch-off.

  • Lower costs: Reduced line rental, cheaper call charges, and fewer maintenance requirements.

  • Greater flexibility: Easily scale channels up or down and enable users to make and receive calls from any location.

  • Improved resilience: SIP trunks can automatically reroute calls in the event of outages, reducing the risk of downtime.

  • Faster deployment: No need for physical line installation, enabling quicker rollout and change