From: bruce@tssnext.rmNUG.ORG
Subject: Re: DISCUSSION: Maximum transmission speed via phone lines
Reply-To:  <bruce@TotSysSoft.com> (Bruce Gingery)
Organization:  Total System Software
Date: Tue, 25 Aug 1992 14:13:23 GMT

wolfgang@netcom.com (Wolfgang Henke) writes:
: andreas@didymus.rmi.de (Andreas Fassl) writes:
: : after hearing about the planned speed for V.FAST (I think app. 28800 bps)
: : I tried to find an article in a german magazine about the maximum
: : possible speed for phone lines published some years ago. 
: : I have in mind something about 120 kbps (maybe more) using the full
: : frequency available on phone lines.
: 
: Here is an earlier post, simply Shannon and some noise figures I deemed
: reliable:
: 
: Newsgroups: comp.dcom.modems
: Path: mork!wolfgang
: From: wolfgang@netcom.com (Wolfgang Henke)
: Subject: Shannon revisited
: Message-ID: <#qajc8mwolfgang@netcom.com>
: Date: Thu, 26 Mar 92 03:23:43 GMT
: Organization: Netcom
: 
: Here are some noise figures taken from the ATT Tech Journal, May-June 1984:
: Central Office C-Message Weighted Metallic Noise (dbrnC):
: 
: Urban	 	10
: Suburban	17
: Rural		19
: Bell System	15
: 
: Here I converted these numbers into the maximum possible data rates assuming
: the modem transmits at -9 db and the maximum legal loss allowed on phone lines
: that is 16 db, so receiving at -25 db. Data rates are in bps:
: 
: Urban		30488
: Suburban	26940
: Rural		26011
: Bell System     28126
: 
: These are 90th percentile figures, so that 90% of callers in the category
: given can expect the data rate given. I assumed 3000 Hz for the bandwidth.
: 
: 

I've barely had a minute to follow these posts, but find the figures intrig-
uing, and seemingly realistic.  It would appear that for better speeds, one
needs to look into direct or optical service...  To extend the above bps table
can anyone confirm these figures I've gathered, or pass back better precision
for the ones which are quite general?  Perhaps I've missed some.


     57600   bps (Max normal rs-232c/v.35 speed/x.25PDN with x.31 hookup)
        64  kbps (Nominal DDS, LATA suport --DS-0 1-voice path)
       112  kbps (SprintNet -- still available?)
       128  kbps (LATA support/DDS/ASDS/T-1 M24-AT&T)
       256  kbps (LATA support/DDS/ASDS/T-1 M24-AT&T)
       384  kbps (LATA support/DDS/ASDS/T-1 M24-AT&T)
       512  kbps (LATA support/DDS/ASDS/T-1 M24-AT&T)
       768  kbps (LATA support/DDS/ASDS/T-1 M24-AT&T)
      1.53  mbps (ISDN basic speed)
      1.544 mbps (T-1 -- DS-1 takes 24 voice paths)
      2.048 mbps (10BASE-2/10BASE-5/10BASE-T/RS-449/v.35/RS-530/x.21/x.25)
      3.152 mbps (T-1C -- DS-1C 48-voice paths)
      4     mbps (nominal token ring/DECnet)
      6.312 mbps (T-2 -- DS-2 takes 96 voice paths)
    9922048  bps (Ethernet - nominal 10mbps)
     16     mbps (nominal token ring/DECnet)
     44.736 mbps (T-3 -- DS-3 takes 672 voice paths)
     51.84  mbps (Bellcore SONET)
    274.760 mbps (T-4 -- DS-4 takes 4032 voice paths)


Oh, and does anyone have the standard Appletalk rates handy?  Thanks.

Bruce
-- 
Bruce Gingery          bruce@TotSysSoft.com        (Total System Software)
InterNet:  Bruce.Gingery@p1.f5.n310.z1.fidonet.org (  Cheyenne, Wyoming )
       or  bruce@brucext.TotSysSoft.com
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