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There is a DECT network at SHA2017 operated by the µPOC, additionally there will be a fieldphone network operated by the Chaosvermittlung

To activate your GAP-compatible DECT handset for use at the SHA2017 telephony network, please register your personal extension at, then just head over to the POC helpdesk at the Infodesk tent.

The POC helpdesk will help you setting up and activating your phone at the DECT network.

Once activated, you won’t only be able to call extensions within the SHA2017 telephony network, but also make free calls to The Netherlands, Germany and probably some other countries.

  • Outgoing call to The Netherlands: 0 <national number incl. 0>
  • Outgoing call to a foreign country: 0 00 <country code and number>

You can also be called from the outside world

  • German Number: You can be reached by calling the number +49 721 266767xxxx. Replace xxxx with your SHA2017 DECT number.
  • Dutch Number: You can request a number via the POC website* (will be available later).

* while stock lasts. Users without a dedicated number can be reached through a shared DID (see below).

Not sure if your phone is supported? Here is a DECT Compatibility list:

Important Numbers

  • 2222 CERT
  • 112 CERT
  • 662 NOC
  • 762 POC
  • 911 CERT
  • 999 CERT

The complete phone book is available at


Like on earlier Hacker Events, the Chaosvermittlung is set out to provide a power independent and low tech phone network.

As some of you might be wondering what the hell is a field phone and why do I want to have one if I already have a SIP/DECT phone we decided to provide a little management summary below.

Field phones are battery powered telephones without a dialing pad connected to a central manual phone exchange. To start your call you have to turn a crank on the side of the phone. An operator will be alerted, answer your call and you can tell him/her which field phone or DECT/SIP number you want to reach.

Now as you know what field phones are you may still be wondering why do I want to have such a device for my OC or village. As mentioned above the phones are battery powered and as we have seen on the CCCamp2015, power cuts can happen. Therefore a power independent communication channel is nice to have. Further more field phones are running on their own copper network and service is not dependant on IP connectivity in contrast to the SIP desk phones. We are also planning for a battery powered GSM uplink for outbound calling.


As we have a limited Amount of Ports on our manual exchange (60), wie like to have people telling us if they want to have a fieldphone connected (either your own or a loan device). There for if you want to have a port enter yourself in the table below.

# own device Nickname/Village/Cluster DECT (for Contact) Comment
1 yes POC - -
2 yes Parking - -
3 yes Entrance - -
4 yes Bar - -
5 yes Lounge - -
6 yes Heaven - -
7 yes First Aid station - -
8 yes Radio Studio - -
9 yes Public Phone 1 - -
10 yes Public Phone 2 - -
11 yes Public Phone 3 - -
12 yes Public Phone 4 - -
13 yes Public Phone 5 - -
14 yes Public Phone 6 - -
15 yes Reserve - -
16 yes Reserve - -
17 yes Reserve - -
18 yes Reserve - -
19 yes Reserve - -
20 yes /dev/lol 4020 or 5216
21 yes Chaos-West 1 3893
22 yes Chaos-West 2 3893
23 no AR Village 8997
22 tbd you? tbd

Further information

  • There is also a sip server besides DECT, which you can use with your favorite sip client. When registering your extension, please choose "SIP Account" as extension type. The server runs at
  • There is also a good chance to enjoy DECT coverage even at the parking lot.
  • Blog: Bring Your Own DECT: registration is open

Behind the scenes

  • Alcatel OmniPCX 4400
    • Multiple chassis from VH to ACT28
    • Redundant CPU7-2
    • multiple DECT4HB line cards
    • multiple DECT8 line cards
    • single mode fibre connection between the different chassis
  • 1RU server with PRI card to connect the chassis to the local sip server.
  • sip uplink kindly provided by speakup.


  • 2x 30 Port Manual exchange
  • 2x 4 Port DECT Uplink

Shared DID

Phone users who don't have a national number (see above) can be called from outside the SHA phone system via a shared DID: First dial +49 32 222 130 066 and wait for the prompt. When prompted, dial the extension you want to reach, followed by the pound sign or hash key. Note: this service is not operated by the POC team, so don't complain to them if it doesn't work. Instead, call DECT 3732 for help.