Contact / Impressum

German law (§ 6 Teledienste Gesetz) requires any website to have an Impressum. The paragraph below is the Impressum of this website.

NOTE: The contact address below is only the legal contact, and not responsible for any technical inquiries.
See for the mailing lists used for technical inquiries

Contact Address

The operator of this website can be contacted by the following means:

Postal Address

Harald Welte
Glanzstr. 11
12437 Berlin



(NOTE: Phone calls are generally not answered, unless scheduled in advance via email or Fax)




Legal Notes

Licensed Spectrum

GSM, TETRA and other systems operate in licensed frequency spectrum, i.e. the license to operate equipment on those bands is granted (typically sold/auctioned) to commercial entities.

This is very different from technologies like Bluetooth or WiFi operating in the 2.4GHz unlicensed ISM band.

As a result, you cannot operate any GSM RF equipment (like the BS-11 or any other BTS) unless you have obtained a proper license from the regulatory authority in your country. Accomplishing to operate a BTS without having such a license is subject to punishment according to the respective laws in your country.

Apart from the legal aspects, there also are practical aspects. If you operate on a channel (ARFCN) that is already used by a GSM operator, you will likely create interference with the production network. Please don't do this! It is illegal and disruptive, and not related to what this project is trying to achieve.

Interfering with a public telecommunications network, intentionally or unintentionally, is a crime in most countries and punishable under applicable law!

Regulatory authorities for spectrum licensing

GSM Related Patents

Osmocom software is Open Source software for research purpose, not a product that is used commercially. The development is done by volunteers who want to learn more about GSM and who want to encourage others to experiment with it.

As such, Osmocom software does not come with patent licenses of any sort. It is well known that mobile telephony and GSM specifically is a patent minefield. Some of those patents relating to voice codecs and the Um air interface are already licensed by the BTS manufacturer. Other patents might apply directly to what OpenBSC or other Osmocom projects are doing.

If you are using Osmocom software in a commercial setting, it is your responsibility to properly license all applicable patents from their respective holders. The ETSI maintains a list of essential patents that apply to GSM.


The software and information published on this website is only to be used within the scope of applicable local rules and regulations.

For example: In Germany the unauthorized interception of radio transmissions is a felony under law!

Please observe laws and regulations. Under no circumstances are the authors of the software responsible for illegal use.

The point of our research is not to increase the illicit eaves-dropping on professional mobile radio, but to outline the security weaknesses, and to enable everyone to confirm our findings.