In 2016 and 2022 I participated in a project called “Cosmic Cable Ldt.", a fictional company which provides telephone booths at Fusion Festival. This was one of the most varied and beautiful projects I’ve ever done as it combines work with metal and wood, art and decoration with a technical stack from old dial phones to modern VoIP networking. As I love doing all of this at once, working in a small group of friends on a weird techno festival environment fits me just perfect.

About Cosmic Cable Ltd.

Comsic Cable is the lost cause of a post-bureaucratic telephone network provider mostly run by a crew of rogue technicians. Founded in 2016 as an alternative to the bad mobile network at Lärz, Germany it provides the most stylish telephone booths at both Fusion Festival and at.tension Festival to connect guests and crew. The telephone network is complemented by additional well-known Cosmic Cable services like the “Status Box” which provides asynchronous communication for guests as well as yearly changing entertainment options.

Github Account:

Technical Setup

Within the Cosmic Cable network everything starts with a classic rotary dial telephone. Although dial phones are awesome, there exist considerably constraints when using them. The most important is that with pulse dialing you can only dial once per call. The moment the dialing is complete you can not dial additional numbers, what prohibits any kind of interactive menus.
Since building a whole analogue telephone network is very time consuming we use old Fritz Boxes to adapt the telephone to a TCP/IP based network. Models which are known to work well with pulse dialing are e.g. Fritz Box Fon ATA.

From then on the we can use all kinds of standard networking gear. On the festival site we often use Ubiquiti Nanostations to establish radio links when no cable links are available.

As a software PBX we run a Asterisk setup which implements the service features that Cosmic Cable offers. The configuration is available publicly on Github.

Another important part of attractive telephone booths is the audiovisual ringing which combines the classical ringtone with some other effect like blinking lights or a flamethrower. To trigger such events we have used two different concepts over the years.

First we had selfmade relay or other driver PCBs on the second analogue port on the Fritz Box. The Asterisk server then automatically called the corresponding number on specific events.

Later on we developed the so called Mystery Box which has a analogue telephone pass-through and a 12V output which is constantly toggled as long as there’s ringing on the line. The box also provides connection terminals for 12V powered light as well as a passive POE injector to drive the Nanostations.