Weblink for assembly http://www.linux-call-router.de
Description: Provisioning of voice and telephony services
Organizational information
Orga contact jolly@eversberg.eu
Area 1d
Things we bring ISDN equipment, TTY, OsmocomBB-Equipment
Local workshops/lectures no
Planned workshop/lectures TBD
Member seats 6
Lecture seats
Power consumption
Planning notes TBD
Other Assemblies


External Telephony connection

We will provide external telephony connection this year. A primary rate ISDN connection (30 calls at a time) is installed, the hardware is tested and deployed.

Location and Seats

We like to be located close to the PoC, in order to simplify communication with the PoC and to manage GSM helpdesk togeter. This requires 6 seats. Further, we will bring a teletypewriter to send SMS and a classic telecommunication announcement machine with several phones connected to it. Both machines+phones require about 3 meters of additional table space.

What we do

Again we will provide external telephony connection to the congress by linking the DECT base station of Eventphone (POC) to T-Com via ISDN over IP tunnel. You will be able to dial to the national fixed and mobile telephone network for free, except value added numbers and emergency numbers. Just use your DECT phone as you would do it at home.

Also we will connect the GSM test network (using OpenBSC) with the DECT and public network. (The GSM network will be setup by the OpenBSC people. It will be officially licensed by the German regulation authority BNetzA.)

The connections are both realized with Linux-Call-Router, a software based PBX, specially designed for ISDN/GSM and low latency. In conjunction with mISDN driver, it connects to E1 links (S2M), S0 links, virtual IP links, as well as to Asterisk PBX using chan_lcr channel driver for SIP and other protocols.

Use your DECT Telephone

To dial to a German number, just dial the area code and number as you would do elsewhere in Germany. For Hamburg you also need to dial the area code! : Example: 040 1234567 (dialing to Hamburg) For our foreign visitors: In Germany the area code always starts with the '0', so if you like to dial an German number like +49-xxx-yyyy, then you remove the country code (49) and add the '0' for accessing the area: 0-xxx-yyyy'.

To dial inside the congress, you need to dial the four digits code of the phone you like to reach. (Don't add 0 or any other prefix in front of it.)

To dial to the congress from German telephone network, dial 040-231889-xxxx, where xxxx is your phone number at the congress. To dial from outside Germany, dial your international access code and then +49-40-231889-xxxx.

Use your GSM Telephone

To register an extension number for you GSM mobile, visit the Eventphone Guru. One you have registered, trigger you manual network search on you mobile phone. Select the network "262 42". Now you need to dial your received token (from the Eventphone Guru). The network will then assign your extension number to your mobile subscriber identity (IMSI).

Special Projects this year

Interoperability test with OpenBSC

An interface allows Linux-Call-Router to use OpenBSC and a Base Stations to build a GSM network with access to ISDN/DECT phones and the public fixed network. We like to test and improve stability of both GSM and Linux-Call-Router, as we did last year.


The major work of last year was implementing a GSM protocol stack of the mobile phone. Together with some phone's hardware, it is possible to log into a GSM network and make / receive calls and SMS together with a valid SIM card. We will show this in practice. This stack is opensource and available at OsmocomBB website.

MOC (GSM Helpdesk)

We will help to use GSM network and answer questions.

Visit us

Further more we will show the Linux-Call-Router software and how to connect it to Asterisk.

Contact us

  • jolly AT eversberg DOT eu
  • before and during congress: +49-4644-973171


Archived page - Impressum/Datenschutz