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Good evening. For years - specifically since 2005 - the eventphone crew has been using the rather versatile software PBX Asterisk. It provides flexible scripting support, SIP trunking, mISDN and many more features desperately needed for our telephony setup. At first we connected the 4400 (proprietary PBX) to Asterisk 1.2 via mISDN1 and Cologne Chip E2 - that was around WTH 2005. For some reason, Asterisk had to be started within a 'while true' loop at the hacker event. I wonder why. As the years passed, mISDN (Linux kernel ISDN driver) and Asterisk's chan_misdn module were taking turns to being incompatible with each other. One time we happened to observe audio bit calculation errors increasing with each ISDN channel used. With 2 channels the error may not even be heard, but we had 30. Lucky for us there has always been a suitable combination of mISDN, chan_misdn and Asterisk, which worked for us. Then, a few years later Jolly renamed isdn4linux to LCR (Linux Call Router) with heavy enhancements. And LCR comes with its own Asterisk channel module chan_lcr. At the same time Asterisk's chan_misdn stopped being maintained. So we switched to the slightly more complicated but surprisingly stable setup 4400--LCR--asterisk. Although, during hacker events, the 'while true' was still in place. This year, LCR added SIP support. And the 29c3 is near. I will only add this much to the rumour mill: PoC-Apps have already been updated.

It's just one of those spring days where your may wonder how to control your friendly BlinkenLights neighbourhood building with Asterisk. Ordinarily the installation comes with a control program called BlinkenLights Chaos Control Center (BLCCC) which can be seen as a jukebox controller handling movies and games. The BLCCC expects incoming ISDN phone calls to be relayed by a UDP based protocol. A suitable Asterisk AGI application can now take over the role of a mediator between ISDN and BLCCC, thus transparently substitute a real ISDN line.

The PoC version of this mediator program is the newest extension to the PoC Telephony Application Suite.

A growing number of telephony applications primarily developed for the Phone Operation Center is now freely available on sourceforce: poc-apps.sf.net. As of now you can download the maze (english+german), spoken human rights (german) and a small time announcement application from the SVN repository. The maze has been solved to the very end only about twice since its first appearance in 2005 at the annual Chaos Communication Congress (22C3). Moreover the in-game phrase "Du stehst vor einer Wand." ("You're facing a wall.") is well known as it has been cited numerous times at the 22C3 and similar gatherings.

The code so far is written in Tcl as Asterisk AGI, however there is no need to know either Tcl or AGI in order to use the application. More about Asterisk may be found in the Conceptual Introduction to Asterisk.

After quite some time now, this is not only yet another comment about the world and its inhabitants, but foremost the attempt to bring the world a little closer to each of us by seamlessly spilling bits and pieces of information commonly referred to as knowledge. And what knowledge would suit better in this context than the one about intriguing means of communication?

The Asterisk Open Source PBX has been around for some time now, even forked once or twice. However in order to truly grasp its inner secrets your can now start by reading this Conceptual Introduction.

Enjoy the ride.