Linux, Networking Leave a comment

IPv6 – good bye SixXS, hello Hurricane Electric

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I’m using IPv6 through a tunnel from SixXS since some time. Unfortunately they decided to stop this service on June 6th. As my beloved provider regrets to provide native IPv6 (nobody needs this, nobody wants this) I had to find another solution – and here it is: Hurricane Electric Free IPv6 Tunnel Broker. It’s done with three simple steps.

  1. Request a tunnel with an endpoint near to you from a list – ready within 5 minutes.
  2. Enter the tunnel details into your router, e.g. a Fritz!Box
  3. Call an URL on every IPv4 address change, a Fritz!Box can do this automatically:
    https://USER:SECRET@ipv4.tunnelbroker.net/nic/update?hostname=TUNNEL_ID

Have fun and teach the turtle to dance 🙂

 

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IPv6

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Letztens habe ich mal wieder den sehr informativen IPv6-Podcast CRE 197 gehört. Für uns arme IPv4-Opfer wird dort der Tunnelprovider SixXS empfohlen. Ok, nun ist es bei mir auch an der Zeit -> Tunnel beantragt, in die FritzBox eingetragen und – dada – IPv6 über den IPv4-only DSL-Zugang.

Hardware 7 Comments

Tuning a Cheap USB Audio Interface

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Some years ago I got a cheap UCA202 audio interface from Behringer. Unfortunately the Burr-Brown (now TI) USB audio codec pcm2902 is broken by design. The internal voltage reference shows a terrible distortion because the 1 kHz usb clock isn’t decoupled properly. The data sheet recommends the use of an external voltage reference for a high-performance application (figure 37) – unfortunately Behringer uses the circuit for a simple application (like figure 39).
I tested my UCA202 with jaaa, a great tool written by Fons and got a “nice” peak at 1 kHz – it went away after adding a reg103-a to my UCA (you can get free samples from TI).
If you compare figure 37 and 39 of pcm2902 data sheet you’ll see the difference. I’ve soldered the two resistors 27k and 13k directly onto the IC1 (these devices are SMD parts – I had to use a magnifying glass an a very fine pitch soldering iron) and made a connection to the pcm2902.
You can substitute the voltage regulator by any other low drop type – the enable input isn’t imperative. The pcm2902 codec needs about 3.6..4.0 volts at pin 10 to override it’s internal voltage source.
Good luck.