Newsgroups: sfnet.tietoliikenne.yhteydentarjoajat,sfnet.keskustelu.asuminen
Subject: Re: Taloverkkotekniikat ja tarjoajat [Was: Viel�    kerran HomePna, nyt tarjoajat hukassa]
References:    <[email protected]>  <[email protected]>  <[email protected]>  <[email protected]> 

jatkoa aikaisempaan viestiini:

> > Voidaanko kantataajuiseen ethernetsignaaliin suodattaa puhekaistan
> > kokoinen "kolo" bittivirhesuhteen siit� k�rsim�tt�?
> 
> Kyll� onnistuu. Itse asiassa 10Base-T Ethernetin linjakoodaus on 
> sellainen, ett� signaalin energia on 5 MHz ja sit� suuremmilla 
> taajuuksilla. Kyseisell� Manchester-koodauksella energia on 
> p��asiassa 5 ja 10 MHz paikkeilla, ja tuota ylemmillekin taajuksille 
> menee viel� energiaa (signaali joka systeemist� l�htee ei ole 
> ihan puhdasta sinimuotoista, enemm�n v�h�n k�sitelty� ja suodatettua 
> kanttiaaltoa). 
> 
> Eli 10Base-T Ethernetiss� tuo signaali liikkuu jo eri taajuuksila 
> kuin puhelinsignaali, eli puhelimen kaistalle ei tarvitse 
> varsinaisesti leikata mit��n pois, kun tuolla 300-3400 Hz 
> taajuuksilla ei satu Ethernetiss� olemaan alunperink��n signaaleita 
> (eik� Ethernet-korttien linjamuuntajatkaan p��st� oikein 
> noin matalia taajuuksia l�pik��n). 

Ethernet yl�taajuuksila tekniikka vaikuttaisi muuten olevan 
USA:ssa jopa kaupallisena tuotteena nimell� ETS Data Piggyback
josta tuotteen esite l�ytyy osoitteesta 
http://www.etslan.com/downloads/edp001.pdf
"The Data Piggyback technology, only from ETS, permits transmission of
10BaseT (Ethernet) signals across already-installed ordinary telephone
wiring, while voice connectivity continues uninterrupted. Using
frequency combination and separation techniques, two pairs of wire can
carry a single data connection (transmit and receive pairs), as well
as two phone connections."
"Residential systems and many hospitality and other commercial
installations operate flawlessly with this equipment. However, ETS
Data Piggyback units are not compatible with most PBX systems that
use high-frequency signaling for control functions."

Tuotteen tekniikasta jutusteua enempi osoitteessa
http://www.etslan.com/jc000007.php
"The problem with telephone networks is that they usually cannot
support high rate data (10BaseT Ethernet) and voice service together,
leading to a need for rewiring in order to accomodate data services."
"Energy Transformation Systems (ETS) has solved the problem for many
MTU's by developing a family of products that directly address the
requirements, without the expense of rewiring. In most cases we allow
a "No New Wires" installation."
"ETS has some clever folks, and we created patentable products
utilizing extremely simple passive circuitry, permitting simultaneous
voice and data on either one or two pairs of existing wiring."
"We call our technology PairSavers �. The first product group is
designed to send data over a single pair using our Monoline �
technology. Another product uses freqency separation to share data and
up to two voice channels over two pairs using our Data Piggyback �
technology. The third product family combines the two technologies
into our Monoline Piggyback � technology so that both voice and data
can be combined on a single pair of POTS line. [POTS is a nickname for
plain old telephone service.]"
"Envsion the ETS solution: A simple wallmount panel
installation in the wiring closet interrupts the existing wiring to
put the ETS circuitry inline with the existing phone system. In the
suite or apartment, your installer removes the existing wallplate,
reterminates the wiring to the pre-assembled ETS wallplate, then
attaches the plate to the box."

> Ainakin teoriatasolla 
> tuossa Ethernetin taajuuksien alla voisi kulkea muitakin 
> telesignaaleita, mieleen tulee ISDN ja tai ADSL samassa 
> kaapelissa, kun suotimet ovat sopivat. N�m� kaksi 
> j�lkimm�ist� teoriatasolla voisi olla mahdollisia, 
> ei ole tullut testattua k�yt�nn�ss�. 

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/