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Daily Digest Archive for April 9, 2003
Q: (Initially posted on April 2, 2003) FROM MENTEE
ALMIRA S. IN NY
Technology has recently allowed us, or is beginning to allow
us to not only
talk on the phone, but to also send a picture of yourself, so
you are in a
way watching a movie clip of who you are speaking to. I understand
how you
can talk on the phone, but how does this technology work? |
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April 9, 2003
A: FROM MENTOR JOAN LUSK IN
RI
Having let the previous question on how e-mail works languish
unanswered for so long just because I didn't know the answer,
I'll
just jump right in on this one! I'm still only an amateur
at
telecommunications technology, but I'll dare this much: Telephone
signals nowadays are mostly digital. The sine waves that carry
sound
through the air are converted into a series of binary numbers
and
sent along the wires, along fiberoptic cables or through the
air as
packets of ones and zeros, to be decoded at the receiver and
turned
back into sound waves in the air. Pictures too can be digitized;
so
can moving pictures (just a series of pictures, after all),
even with
(digitized) sound. Think of movies on DVD (Digital Video Disk).
So
these new picture phones must be able to record, send and
decode the
string of numbers that encodes each picture, as well as the
string of
numbers that encodes the sound of your voice. Pretty neat
stuff.
Here's a site from AT&T telling the history of telephone
technology
http://www.att.com/attlabs/reputation/timeline/70picture.html
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