Autor: Suave Lobodzinski (slobo_at_csulb.edu)
Data: Wed 05 Oct 1994 - 23:45:12 MET
Kilka tygodni temu otrzymalem sporo prosb o informacje na temat
wykorzystania kabli telewizyjnych do przesylania danych w zastosowaniach WAN.
Technologia ta jest jeszcze w powijakach, ale wiazane sa z nia duze
nadzieje (patrz nizej). Pierwsza instalacja na CTV modem w OrangeNet
bedzie podlaczenie szpitala (500 lozek) do Internet planowane na Czerwiec
1995.
Oto "summary" tego co jest dostepne obecnie na rynku amerykanskim:
1. Routers
DEC oglosil ChannelWorks router ($6,995) ktory pozwala na podlaczenia do
sieci TCP/IP z predkoscia 10Mbit/sec. Router dziala jako przedluzenie
Eithernet do sieci telewizji kablowej. ChannelWorks obsluguje SNMP
i inne podstawowe protokly sieciowe. Jest to system "full duplex"
funkcjonalnie identyczny do Eithernet.
2. Modems
Intel, Sophie i kilku innych producentow czekaja z oficjalnym ogloszeniem
swoich duplex modems do COMDEX (11/12/94). Oto "press release":
Orange Countr Register 5/30/94
Soon people will be able to plug the cable television line into the back of
the family computer and get faster, cheaper access to a range of
services. Several companies are developing powerful devices, called
cable modems, that link personal computers to cable TV lines to bring this
about. They showed them off at the National Cable Television Association
convention last week in New Orleans. Cable modems can move text, voice
and pictures 1,000 times faster over cable TV lines than standard
telephone modems. "The cable pipe is fatter," said Avram Miller,
a vice president of Intel Corp., which is developing a cable modem with
General Instrument Corp. Digital Equipment Corp. is developing its own
cable modem and Zenith Electronics Corp. has one completed.
Intel and Digital executives expect to have cable modems in stores next year.
Zenith plans to sell its modems to cable systems, which would rent or
sell them to consumers.
Cable modems are expected to be priced at $500 and up. The devices are
attracting attention from online services,such as ANS, PSI, CompuServe
and Prodigy, retailers and cable companies, which see opportunities to sell
more services to the public.
Intel's and Digital's modem shouId move more than 10 million bits of
information a second. Developers believe cable modems will change the way
people use their computers. Digital's Jim Albrycht said cable modems are
the first step to converting the computer into a device that people will
use to watch TV.
"The next generation of television will be the same as today's PC, except
with a large screen for viewing. And, it will be in the living room as
opposed to the family room" Albrycht said.
Associated Press writer Jeannine Aversa and Register news assistant Liisa
Puckett contributed to this report.
Istnieje rowniez cos "in progress" zwane VODEM:
The Vodem (VideO DEModulator) is a device that allows for the
simplex (one-way) delivery of information over a video carrier.
Just as a modem uses the funny tones over the phone lines to
carry information, so does the Vodem over cable television.
Unlike the modem, however, the Vodem only broadcasts in one
direction and is not designed for interactive applications.
WHY WOULD I WANT A VODEM ANYWAY?
The vodem, although unsuited for interactive applications, is
ideal for asymmetric applications such as Usenet News/Mail delivery,
File Transfer, and the delivery of information from a single
site to many diverse sites. The first project using this
technology is called the Vodem Project and is dedicated to
putting together a system that will deliver a full usenet news
feed (or a partial feed, if you want) to the information
consumer for a total system cost of under $150, and a monthly
fee between $5-$10 (we hope - it depends on the carrier).
HOW IS THE VODEM DIFFERENT FROM THE OTHER CATV SYSTEMS
The Vodem is:
a) FCC approved
b) Patented
c) Ready to be produced (once software development is done)
d) Cheap! Under $150
e) a technology requiring no modification to existing
cable television plants.
HOW FAST IS IT?
The Vodem has three protocols, each with a different speed:
Vodem.slow - a 50KBPS protocol for dirty video transmission
Vodem.normal - a 90KBPS protocol for reasonably clean video signals
Vodem.fast - a 175KBPS protocol for error-free video signals
At its slowest, Vodem is almost as fast as a 56K modem line and
under normal conditions can download a 100k file in under 9 seconds,
a 1MB file in about 90 seconds (using Vodem.normal protocol).
Pozdrowienia
/\
/ ^\ /\
/^ \ / ^\
/ ^ ^ \/^ ^\ OrangeNet -Finest Internet Connectivity in OC
/ ^ ^ ^ \ ^ ^ \ S. (Suave) M. Lobodzinski, Ph.D
/ \ \suav_at_orange.digex.net, slobo_at_csulb.edu
/ ^^ ^ ^ \__________________________________________________
/
kk
To archiwum zostało wygenerowane przez hypermail 2.1.7 : Wed 19 May 2004 - 15:46:14 MET DST