V.Fast & V.Ter

V.Fast & V.Ter

Post by Tim Frie » Thu, 11 Nov 1993 07:20:23



I'm late hearing about this stuff...

Could someone please post a description of what these (proposed) standards say.

Specifically, speeds before and after compression, backwards compatibility with
V.32 and V.42bis...  How they handle low quality phone lines, etc...

 
 
 

V.Fast & V.Ter

Post by Richard Threlke » Wed, 17 Nov 1993 19:10:24



> I'm late hearing about this stuff...

> Could someone please post a description of what these (proposed) standards sa

> Specifically, speeds before and after compression, backwards compatibility wi
> V.32 and V.42bis...  How they handle low quality phone lines, etc...

V.Fast is based on draft copies of the new V.34 standard which allows
a "pump" speed of 28.8kbps (vs. 14.4kbps for most current modems).  It
will probably not be compatible with V.34 when it comes out.  No
modems are currently shipping with V.34.  Expected time is late
first quarter to early second quarter.

V.terbo is an attempt to optimize the existing chipsets to get higher
baud rates.  It gets a pump speed of 19.2kbps (and USR's proprietary
add-ons get to 21kpbs).  Add V.42bis compression and you need the
ability to run 115kpbs between the modem and the computer.

The real issue, according to people implementing V.34, is that the
chips used to achieve V.32bis and V.terbo are not powerful enough
for V.34.  It is estimated that approximately 3 times the horsepower
will be required to fully implement V.34.  The current V.FAST
modems do not have that extra horsepower and will require
the same redesign that the others are performing.

-------------------------------------------------------

Don't pay any attention to that man behind the curtain. (Oz)

 
 
 

V.Fast & V.Ter

Post by Tony Zuccari » Thu, 18 Nov 1993 11:16:06




> The real issue, according to people implementing V.34, is that the
> chips used to achieve V.32bis and V.terbo are not powerful enough
> for V.34.  It is estimated that approximately 3 times the horsepower
> will be required to fully implement V.34.

Probably more like 4 times.

Quote:> The current V.FAST
> modems do not have that extra horsepower and will require
> the same redesign that the others are performing.

I wouldn't make that assumption at all. Rockwell V.FC modems can achieve
up to 28.8kbps 'pump' speeds only by employing V.FAST/V.34 class
technologies and therefore have the horsepower by default. I would guess
that
other >19.2kbps full duplex dial-up modem implementations have similar
increases
in horsepower beyond V.32bis or V.32terbo. You won't get 28.8kbps by using
V.32bis/V.terbo DSP horsepower.

--

Product Marketing                                    
Rockwell International

"The above comments do not necessarily represent
 Rockwell International, but are my personal views."
---------------------------------------------------------------------------------------------------------------

 
 
 

V.Fast & V.Ter

Post by Christian Weisgerb » Mon, 22 Nov 1993 20:54:33



> V.Fast is based on draft copies of the new V.34 standard which allows

"V.Fast" was the nickname for V.34 before the ITU had decided on the
name. There are no V.Fast modems just proprietary technologies
approaching speeds as envisioned with V.Fast aka V.34.

--

 
 
 

V.Fast & V.Ter

Post by Sandeep Pomb » Thu, 02 Dec 1993 11:24:46


I would like to get information on ERROR Charactersitics of V.FAST modulation
scheme. In particuler can I use a Reed Soloman FEC scheme and hope that
I have corrected all the erros for 99.99% of Lines in US. I would like
to use a code such as (245,256). Also are the erros bursty?
                Thanks
                        Sandeep Pombra