ISDN shutdown & IP changeover What you need to know now

The telecommunications industry is on the home stretch of the biggest migration in recent years, the switch from ISDN to All-IP. Against this background, more and more customers are receiving a letter terminating their ISDN telephone connections. What does this mean for those affected?

Why is there the All-IP changeover?

Deutsche Telekom AG, the largest telecommunications provider in Germany, announced in 2015 that it would switch off ISDN by 2018. The aim was and is to consolidate different networks / technology platforms on the uniform IP technology in order to save significant costs. In addition, ISDN technology was no longer developed by the hardware partners of the telecommunications companies.

But the dead live longer, so that business customers in particular are currently still using ISDN connections. But Deutsche Telekom is pushing the pace here too and wants to have the entire changeover completed in 2020.

EXTRA: 5G for everyone ?! Consumer advice center calls for complete internet expansion

Different migration alternatives

When converting to IP you have – in addition to the selection of various providers – also three technical variants to convert your previous connection:

1. Sip trunk

Modern telephone systems offer – if necessary. through software upgrade – the possibility of storing a so-called Sip trunk in the TK system. You can apply for this at the telephone company and you will then receive the corresponding access data. The PBX must then be connected to a data internet line and you can already make calls via IP.

2. Gateway solution

If you are still using a relatively old ISDN telephone system and do not want to make any investments at the moment, the gateway solution is ideal. The respective telephone company installs a so-called media gateway for this purpose, which “speaks” in the direction of your ISDN telephone system and “translates” into IP in the direction of the telephone network.

This solution saves you time and you can always switch to an IP telephone system (with SIP trunk) or IP Centrex later.

3. IP Centrex

IP-Centrex is a cloud telephone system, which means that apart from IP telephones, you no longer have any hardware in your office. The software is stored on a multi-client system in the cloud, which is accessed during every call. With this solution, you usually pay per user per month.

What should I do now for the All-IP conversion?

It depends on your current situation:

Threat of dismissal

If you have received a threat of termination without a clear termination date, it is important to act promptly. That means you should deal with the topic:

  • Will I stay with my previous provider?
  • Which of the different migration alternatives suits my company?


If you have been given a clear termination date, you should act immediately. The providers are mostly serious here and your connection is actually switched off.

If the termination date is within the next 8 weeks, you usually have little other options than staying with your previous provider. It is important to quickly find the most suitable migration solution.

Notice of termination or termination not yet received

This occurs, for example, with Vodafone, 1 & 1 Versatel or regional providers. There is initially no pressure to act. Nevertheless, it makes sense to deal with the topic, as you will probably be confronted with it for the next two years. So you can calmly check providers and techniques and if necessary. testing.

Are alarm systems, fire alarm systems, etc. affected by the IP changeover?

When switching to IP, you must pay particular attention to any special services that may be used. This includes:

  • Alarm systems
  • Fire alarm systems
  • Payment system (e.g. EC-Cash)
  • Elevators
  • Home emergency systems

With all of these services, a changeover to IP usually does not take place or cannot take place automatically. You must therefore contact the respective manufacturer of the special service BEFORE the changeover and clarify what options there are for the changeover.

Opportunity for improved communication

As a person affected, you should deal with the topic as soon as possible, especially if a letter of resignation flutters into the house. One thing is certain: You will be switched to All-IP, whether you want it or not. So you should consider the changeover as an opportunity if possible and consider how you can improve the flow of communication in the company, for example within the framework of unified communication.

Leave a Reply

Your email address will not be published.