mgs
[Top] [All Lists]

Re: 56K Line Speed?

To: Chip Old <fold@bcpl.net>
Subject: Re: 56K Line Speed?
From: Mike Razor <mrazor@kih.net>
Date: Sun, 14 Feb 1999 11:02:57 -0500
Thanks for the explanation.  I think the culprit is my ISP.  They must only
operate at 28000.  I have asked them twice what speed they operate and they
never respond so I assume they think that it is a dumb question.  Kind of like
what does this thing called a speedo do (MG content).
THANKS!
MIKE R

Chip Old wrote:

> On Sun, 14 Feb 1999, ccrobins wrote:
>
> > How is everybody doing on this?  I bought a 56K v.90 MODEM and the
> > best it ever gets on at is 493000. Spld another identical MODEM to my
> > neighbor lady and it never gets on at better than 48000.
>
> Oh boy, talk about off topic!  I'll probably catch hell from someone for
> replying, but it's something that probably affects a lot of you.  I'm an
> ISP, so I deal with this question every day...
>
> Assuming your ISP has V.90 modems at his end, then 56,000 bps is the
> maximum possible connection speed you can theoretically get.  That doesn't
> mean you should expect 56K connections.  In fact you will never see a 56K
> connection, and if you really are getting 49,333 bps then you are
> extremely lucky.  Very few V.90 users ever see that speed.  The average,
> according to industry surveys, is in the 44,000 - 48,000 bps range.
>
> When two modems connect they negotiate a connection speed that is reliable
> under the conditions they find on the phone line at the time, and/or a
> speed that is workable given the level of compatibility of the two modems
> involved.  Once that initial connect speed is established, the modems
> renegotiate constantly to adjust to changes in phone line condition.  What
> your dialer software reports is the initial connect speed, but the speed
> actually changes constantly during the course of your online session.
>
> Any number of phone line conditions can prevent you from getting
> connections as fast as you might like, but line noise is the biggest
> culprit.  If you are on a noisey line, then your modem and the ISP's modem
> will negotiate a slower speed to compensate for the interference caused by
> the noise.  In the case of a 56K modem, if there is more than one analog
> to digital conversion between you and the ISP, or if the distance between
> you and the local switching office for your telephone exchane is too
> great, then 56K connections will be impossible and you will be limited to
> V.34 (33.6) connections.  If noise is the problem, you may be able to get
> your local telco to fix it.  If too many analog to digital conversions or
> too great a distance is the problem, then you're out of luck.
>
> The other major issue at this stage of V.90 development is incompatability
> between modems.  True, V.90 is an industrywide standard, but the modem
> manufacturers are still trying to figure it out.  The result is minor
> incompatabilities between modems from different manufacturers.  To
> overcome this, most V.90 manufacturers are releasing new versions of their
> firmware all the time.  If you want to play the V.90 game successfully,
> you must be willing to upgrade your modem firmware every time the
> manufacturer releases a new version.  Even then there are no guarantees,
> but the situation is improving steadily.
>
> -----------------------------------------------------------------------
> Chip Old                      1948 M.G. TC  TC6710  NEMGTR #2271
> Cub Hill, Maryland            1962 Triumph TR4  CT3154LO
> fold@bcpl.net




<Prev in Thread] Current Thread [Next in Thread>