TU Darmstadt will soon be telephoning via Internet

Conversion of telephone connections from ISDN to VoIP


The TU Darmstadt is expected to switch its telephone connections from classic ISDN to encrypted VoIP in mid-July.

The changeover to IP telephony will take place in two phases:

Phase one:

  • All external connections from the university's regional telephone network will in future run via VoIP.
  • All incoming connections from external sources will continue to run via ISDN.

Phase two (approx. 2 weeks later):

  • Conversion of the exchange number 16-XXXXX to VoIP
  • All incoming and outgoing connections are handled via VoIP.

What is going to change?

With regard to the authorization classes as well as the telephone costs, there will be minor adjustments due to the conversion. The telephone numbers will not change.

In terms of costs, we do not expect any noticeable changes in the national area. Most connections, especially international connections, will even become significantly cheaper. Due to the fair flat rate (limitation of the monthly telephone charges to max. 25 €) there is an additional cost security for you.

Instead of 14 authorization classes so far, there will be only six classes in the future. The following classes are available for a common telephone connection:

  • International (worldwide without 0900)
  • Germany Mobile and fixed network
  • Germany fixed network
  • In-house (with emergency call facility)

The previous authorization classes will be adjusted accordingly at the beginning of phase 1.

Further information

In this context, we would like to remind you once again of the information on block selection (only german version available).

As soon as the exact changeover dates are known, we will inform you again here and in the HRZ News.