links for 2008-07-11

• A conversation with Jean-Claude Bradley about open notebook science and the educational uses of Second Life « Jon Udell
  Useful conversation between a Second Life skeptic (Udell) and user: what is it about SL that makes if different from (say) a chat room? Comparative discussion other media: blogs, wikis, mailing lists…
  (tags: judell chemistry education secondlife curmudgeon swhpl mynote social comparison wiki ah open audio mp3 podcast listened collaboration free cloud)
• 1ESS switch – Wikipedia, the free encyclopedia
  “For example, a DTMF Receiver, mounted in a Miscellaneous Trunk frame, had eight demand scan points, one for each frequency, and two supervisory scan points, one to signal the presence of a valid DTMF combination so the software knew when to look at the f
  (tags: telephone switch example dtmf touchtone wikipedia how)
• Image:Hilofilter.agr.jpg – Wikipedia, the free encyclopedia
  Television signal splitter, consisting of a hi-pass and a lo-pass filter. I took this picture of an artifact in my possession. –agr 21:01, 30 November 2005 (UTC)
  (tags: saved wallpaper electronics filter example simple lc tv photo good hires circuit wikipedia)
• DTMF – Dual Tone Multiple Frequency
  (tags: dtmf gnb telephone switch how filter touchtone)
• 180px-Ttrcvr-hy.jpg (JPEG Image, 1160×672 pixels) – Scaled (84%)
  via http://en.wikipedia.org/wiki/Multi-frequency_receiver
  (tags: dtmf filter telephhone saved wallpaper electronics via wikipedia 1960s)
• User:Jim.henderson – Wikipedia, the free encyclopedia
  Jim Henderson is the person who put the photograph of the late 1960s DTMF receiver on http://en.wikipedia.org/wiki/Multi-frequency_receiver
  (tags: telephone history dtmf nyc wikipedia)
• The Museum of Communications exhibits antique vintage telephones, central office equipment, teletype and telegraph equipment, antique Western Equipment Company equipment and amateur radio equipment.
  via http://en.wikipedia.org/wiki/Image:Ttrcvr-hy.jpg
  (tags: telephone museum washington switch seattle via)
• ydn-delicious : Message: Re: [ydn-delicious] del.icio.us architecture
  “Delicious is currently a conglomeration of MySQL,
  various internal Yahoo technologies, and a dash of Xapian.

  Regards,
  Toby Elliott
  del.icio.us”

  (tags: del.icio.us database mysql yahoo infrastructure how)