The Datenklo or was an acoustic coupler modem in the early 1980s for which the Chaos Computer Club made plans and schematics available. The moniker 'loo' refers to an ingenious idea in the construction of the device: The use of rubber cuffs, commonly available as plumbing supplies, to connect the audio transducers to a normal telephone receiver.
The meaning of the name changed in the 1990s, when portable toilet cubicles were re-purposed to provide connectivity at in Europe.
The original "Datenklo" (German, in English "data loo") was an acoustic coupler modem for self-assembly. Its name was coined with the schematics provided by the Hacker Bible published by the Chaos Computer Club. The goal of this acoustically-coupled device was to avoid prosecution for the (illegal at the time) connection of an unlicensed device to the telephone line. Compared to certified and legal modems of the time, the Datenklo was comparatively cheap and used the existing landline telephone, making it usable even in a public telephone booth.
The Datenklo name was subsequently repurposed to describe the use of rented portable toilet cubicles to host communications infrastructure at hacker camps. These re-purposed provide connectivity at . This typically includes Wi-Fi and wired communication such as Ethernet. A major event can be served by many data toilets: for example, in 1999 the Chaos Communication Camp had 17 booths.
A typical Datenklo provides a temporary wiring closet for the networking equipment required to deliver pervasive connectivity to hacker camp attendees. They are considered well suited for the demands of an outdoor camp, since they are lightweight and easy to transport, they offer good ventilation, weather protection and are easily locked. Their size allow housing for the typical 19" rack form factor of network infrastructure gear.
Datenklos are interconnected to create the site network, with hacker camp attendees asked to bring their own cables if they would like a wired connection to their tent: Modern iterations show network status and connectivity through the colours of led stripes mounted on top.
Hacker camps are generally organized and run by volunteers known as angels, and the Network Operation Centre angels not only create the network as part of site build-up and tear it down afterwards, but also connect attendees' cables to the switches in the Datenklo.
Many other roles exist for angels:
Whilst wireless networking and Internet protocols have become the norm for voice and data communication, the Datenklo provides hacker camp attendees with the opportunity to build and learn about Plain Old Telephone Service (POTS), turning the Datenklo into a "phone box" of sorts: