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From: rdippold@gdansk.qualcomm.com (Ron Dippold)
Newsgroups: comp.dcom.modems
Subject: Re: High-end Modem Speeds...
Message-ID: <1991Mar21.200217.22686@qualcomm.com>
Date: 21 Mar 91 20:02:17 GMT
References: <9103200803.AA13245@ucbvax.Berkeley.EDU>
Sender: news@qualcomm.com
Organization: Qualcomm, Inc., San Diego, CA
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In article <9103200803.AA13245@ucbvax.Berkeley.EDU> ST7021@SIUCVMB.BITNET writes:
>I am curious to know what the 'real' connection speeds (minus compression, etc)
>of some of today's high speed modems are (Hayes, USR and Telebit, for example).
>I had an interesting coversation with an IBM telecomm guru about six years ago
>where he told me that 9600bps was about as high as normal phone lines can
>handle due to their quality. Is this still generally true? I realize that he
>had given me a number that was in a logical step (2400, 4800, 9600, ...) so
>is there a maxed-out ceiling speed, once again minus compression, etc?

He might have been using IBM standard procedure when talking about quality and
was doing what they usually do:  huge safety margins.  I regularly use my
Dual Standard to connect at 14.4K from and to standard residential lines.  Now
granted, when I have error correction turned on I won't see any errors, but
even with it turned off (just for kicks) it still works fine.  Several BBSes
in town use Telebit Trailblazer 19.2K modems with no trouble.

So:  I think there _is_ more noise at speeds above 2400, but the modems all
have error correction protocols built in, so it really doesn't matter.