ISDN Shutdown Austria: What Businesses Need to Know Now
Andreas Braunizar
Business Development
Summary: The ISDN shutdown in Austria is complete: A1 switched off ISDN basic connections on 31 December 2025 and ISDN multi-connections on 30 June 2026. All businesses using ISDN connections, fax machines, and traditional PBX systems are affected. Alternatives: SIP trunking, hosted PBX, or UCaaS like Microsoft Teams. A professional migration takes 2-4 weeks with no planned downtime.
Is ISDN really being shut down in Austria?
Yes. Austria's major network operators - A1, Magenta, and Drei - are fully migrating their networks to IP technology (All-IP). Germany already shut down ISDN between 2018 and 2020, and Austria is completing the switch now. The ISDN shutdown is not a question of if, but when.
Why is ISDN being shut down? ISDN is based on 1980s technology. Maintaining separate copper lines has become uneconomical for operators, while IP-based networks are more flexible, cheaper, and future-proof.
What is the ISDN shutdown timeline in Austria?
| Period | Milestone | Status | |
|---|---|---|---|
| until ~2020 | No new ISDN connections, new customers receive IP voice only | Completed | |
| 2024-2025 | A1, Magenta, and Drei actively migrate existing customers to All-IP | Ongoing | |
| 31 Dec 2025 | A1 shuts down ISDN basic connections | Completed | |
| 30 Jun 2026 | A1 shuts down ISDN multi-connections | Completed |
Which businesses are affected?
All businesses still using:
- ISDN connections (BRI or PRI)
- Traditional PBX systems with ISDN connectivity
- Fax machines over ISDN lines
- Alarm systems and elevator emergency phones with ISDN dialers
- Card payment terminals with ISDN connections
Many Austrian businesses still rely on at least one ISDN service - often without realizing it, for example in alarm systems, elevator emergency phones, or card terminals.
What are the alternatives to ISDN?
| Alternative | What is it? | Keep existing PBX? | Ideal for | |
|---|---|---|---|---|
| SIP Trunking | IP connection for existing PBX | Yes (SIP-capable or with gateway) | Businesses with working PBX | |
| Hosted PBX | Cloud phone system (no own server) | No (new IP phones) | SMEs without own IT department | |
| UCaaS (Teams, Webex) | All-in-one: phone + video + chat | No (software-based) | Companies with remote/hybrid work | |
| Mobile-only | Smartphones only, no landline | No | Micro-businesses (1-5 employees) |
What does ISDN migration cost?
Costs depend on the number of sites, extensions and phone numbers, on whether the existing PBX supports SIP, on special services such as alarm and elevator dialers, and on the effort for number porting and installation. We quote the price after a short check.
What happens if I do nothing?
- Cancellation by provider: A1 and Magenta are cancelling ISDN contracts with 3-6 months notice
- Rising costs: ISDN tariffs are increasing as legacy infrastructure maintenance costs more
- No new connections: New locations cannot get ISDN anymore
- Outage risk: No ISDN spare parts available for network failures
Frequently Asked Questions
Can I keep my existing phone numbers?
Yes. Number porting is legally guaranteed (TKG 2021). All existing numbers are transferred 1:1 to the new solution.
Will my fax still work after the ISDN shutdown?
Classic ISDN fax machines will stop working. Alternatives: Fax-over-IP (T.38), email-to-fax gateways, or cloud fax services.
Do I need a new internet connection for VoIP?
VoIP requires approximately 100 kbit/s per concurrent call. Any modern broadband connection is sufficient. Recommendation: at least 50 Mbit/s symmetric.
What if my PBX doesn't support SIP?
A SIP gateway converts ISDN signals to SIP. This lets you continue using your existing system until end of life.
How long does the migration really take?
With professional planning: 2-4 weeks with no planned downtime. Self-managed: 2-3 months with increased outage risk.