Worldwide ISDN Switch-Off
What has replaced ISDN?
– SIP is the protocol which most office phones around the world use to talk to each other. A version of that protocol has been adopted by the EBU to replace ISDN for interoperability between broadcast quality IP audio devices.
– ipDTL and sip.audio allow ISDN equivalent audio to be sent and received over the internet with improved audio fidelity, thanks to the Opus codec.
– SIP is the protocol which most office phones around the world use to talk to each other. A version of that protocol has been adopted by the EBU to replace ISDN for interoperability between broadcast quality IP audio devices.
– ipDTL and sip.audio allow ISDN equivalent audio to be sent and received over the internet with improved audio fidelity, thanks to the Opus codec.
United Kingdom
In September 2019, BT Openreach removed the ability for ISDN subscribers to make 64k audio and data calls to international destinations including the USA. In September 2023, they instructed service providers such as BT to stop taking orders for new ISDN installations, ahead of switching off the national network in 2025.
United States
In most states, it is now impossible to order new ISDN circuits. AT&T and Verizon had been pushing up line rental charges for some time for existing BRI customers. In 2017, Sprint switched off their Long Distance ISDN network, with Verizon (formerly MCI WorldCom) serving only legacy customers. The country’s largest radio group iHeart Media migrated all of their stations from ISDN to SIP in 2019.
AT&T’s Global ISDN (GISDN) was the last remaining service for Long Distance domestic and international ISDN calls.
Australia
In 2018, Telstra stopped selling new ISDN services. They are since disconnecting remaining ISDN customers, and expected to have completed the process by 2022.
Estonia
Somewhat ahead of the game, Telia Estonia switched off its PSTN network (including ISDN) back in 2016, having migrated all customers onto VoIP.
Germany
Although the country had relied on ISDN for most of its fixed landline provision, the network had been mostly decommissioned by the end of 2018.
Macedonia
Makedonski Telekom no longer sell or maintain ISDN connections.
Netherlands
KPN began closing down its ISDN network in phases in September 2019. They expected the work to be complete by Spring 2020.
Slovakia
Slovak Telecom no longer sell or maintain ISDN connections.
Spain
Our logs show that the last successful call from our BT lines in the UK to a Telefonica ISDN line, was in August 2019. The last such call from our USA facilities, was in March 2020. Since then, all of our attempts to call ISDN from outside Spain failed.
Sweden
The ISDN network was switched off by Telia Company in the late 2010s. Sveriges Radio now use SIP for all external audio contributions.
