🚀 go-pugleaf

Well, OK, let's re-reemphasize the real point for ISDN Terminal
Adapter (TA) manufacturers, so that future analog modem users upgrading
to ISDN can know better:
 
ONLY A WIMP TA OFFERS ONLY 56KBPS DOSBS (Data Over Speech Bearer Service)! 
The TA needs to be able to attempt a BC=Speech call, then after answer, 
be able to attempt data transfer at 64kbps/B-channel with rate conversion
only at the async/sync border within a given TA! BC=3.1KHz DOSBS should
also be an option (Data Over 3.1KHz Audio Bearer Service).

A REAL TA ALSO OFFERS A 128KBPS DOSBS OPTION. A 112KBPS DOSBS OPTION IS
ALSO NEEDED WHEN THE NETWORK IS NOT CLEAR CHANNEL BRI-TO-BRI.


In article <30DD7720.7949@abtech-dist.com>, <tomallen@abtech-dist.com> writes:
> Path: 
nwestnews.nwest.mccaw.com!nwfocus.wa.com!nwnews.wa.com!news.sprintlink.net!howl
and.reston.ans.net!newsfeed.internetmci.com!news.fibr.net!usenet
/> From: Tom Allen <tomallen@abtech-dist.com>
/> Newsgroups: comp.dcom.isdn
/> Subject: Re: Bitsurfr DOSBS (Was Re: 56k data over
/> Date: Sun, 24 Dec 1995 09:52:00 -0600
/> Organization: ABtech Distributing
/> Lines: 65
/> Message-ID: <30DD7720.7949@abtech-dist.com>
/> References: <4b9ec8$75q@mercury.near.net> 
/<4bci2m$j7l@nwestmail.nwest.mccaw.com> <4bilnc$hep@darwin.i3s.net>
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/> 
/> pat_bouldin@teleteam.com wrote:
/> > 
/> > jcr@creator.nwest.attws.com (Jeffrey Rhodes) wrote:
/> > 
/> > >Fred R.Goldstein has stated: 'Also note that the WinISDN API only
/> > >supports "DOV" at 56k, not at 64k.'
/> > 
/> > >Fred, please help me understand what this means. I could be wrong
/> > >but I thought the WinISDN API only had to do with call setup, not
/> > >with delivery of octets to a COM port. The call setup for DOSBS,
/> > >or DOV as MS likes to call it, does not have to specify the data
/> > >rate. The data rate is something two ISDN users decide after
/> > >experimenting with a couple of different setups and actually
/> > >getting an answer to determine if 64Kbps is actually possible on
/> > >the given circuits of the call that is in progress. DOSBS uses
/> > >either BC=Speech or BC=3.1KHz, which as far as the network is
/> > >concerned, is a 64Kbps PCM data stream. Sometimes the network
/> > >clobbers the least significant bit of a 64Kbps PCM stream, with
/> > >no substantive affect on the voice or fax/modem signal repesented
/> > >by the PCM data stream, which is why DOSBS at 56Kbps is usually
/> > >the only possible data rate.
/> > 
/> > >Is there a WinISDN API call that is used to deliver octets to the
/> > >COM port and does it require the calling application to format
/> > >the octet to 7 bits data, 1 bit filler? If not, then the WinISDN
/> > >API can be used for DOSBS call setup and the calling application
/> > >can directly address the COM port for delivery of user data at
/> > >8000 octets per second using 115,200bps async on a 16550 UART.
/> > 
/> > >Thanks for all your contributions on this subject.
/> > 
/> > >Jeffrey Rhodes at jcr@creator.nwest.attws.com
/> > 
/> > Everyone is jumping around the issue - an understanding is in order.
/> > The whole thing has to do with "telling the network" that you want to
/> > make a "speech" or audio call.  In effect your saying, "I want 3.1 khz
/> > of audio therefore you may use pulse code modulation, adaptive
/> > differential PCM, or any other Belcore approved standard for
/> > delivering the "speech" call.  By asking for clear data delivery your
/> > saying "I want a speech call but I don't really"! You will find the
/> > results of this vary on a case by case basis - BRI to BRI DOSBS works
/> > very well, where BRI to PRI DOSBS stands a HIGH probability of getting
/> > kicked off the ISDN infrastructure, particularly on inter co calls.
/> > 
/> > Finally, the real skinny on speed is simply this:  When making a
/> > speech call (on ISDN), if Bell indeed dumps you out on the digital
/> > voice tandems they may run you through a multiplexer that is using
/> > robbed bit signalling, this will result in an automatic reduction of
/> > "pre PCM'd" (pardon the slang) 56 kbps channels.  If they kept you
/> > whole on a PRI ISDN T1 it would remain intact because the majority of
/> > them run common channel (24th channel) signalling.
/> > 
/> > Hope that helps the understanding.  Bottom line, standards can't
/> > address what the individual PUC's won't approve anyway.  They know
/> > your trying to avoid the tariff.
/> > 
/> > Patrick Bouldin          :    Gig 'em!   TAMU '83
/> > 214/218-6000             :
/> > TeleTeam Internet        :    ARS KM5L _ _ ...    ..._ _
/> > pat_bouldin@teleteam.com :the real issue is that ta's only run at 56k per 
channel async
/> -- 
/> Tom Allen                             Specializing in ISDN,
/> ABtech Distributing                   Lan/Wan Design & Installation, 
/> v 210-599-0123 f 210-599-9310         Internet Access,
/> tomallen@abtech-dist.com              Security
/>