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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!feed1.news.erols.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!cam-news-hub1.bbnplanet.com!howland.erols.net!news.sprintlink.net!news-peer.sprintlink.net!gail.ripco.com!dr From: dr@ripco.com (David Richards) Newsgroups: comp.dcom.isdn,comp.unix.bsd.freebsd.misc Subject: Re: ISDN TA's supported for BSD Unix? Date: 3 Feb 1997 19:01:21 GMT Organization: Ripco Communications Inc. Lines: 36 Message-ID: <5d5cm1$prc$1@gail.ripco.com> References: <dkulp-ya023380000102971144510001@darkstar.ucsc.edu> <5d0nq3$7m2@news-2.csn.net> <5d2goc$fvp@grobbebol.grobbebol> <5d5c9q$eq6@jupiter.dnai.com> NNTP-Posting-Host: rci.ripco.com Xref: euryale.cc.adfa.oz.au comp.dcom.isdn:47671 comp.unix.bsd.freebsd.misc:34649 In article <5d5c9q$eq6@jupiter.dnai.com>, Karl Wiebe <karl@dnai.com> wrote: >bengel@xs4all.nl (Roeland Th. Jansen) wrote: >>In comp.dcom.isdn John J. Rushford <wjjr@bugs.alisa.org> wrote: >>> any special drivers. Also, I believe that you don't get the full bandwidth >>> available on 128K ISDN with a serial connection. >> >>and your belief is wrong in this case. as long as the TA controls the flow >>(cts/rts) -- it's OK. some TA's support data rates at a max of 921k6. > >Is that so clear? Even if your TA is one of those rare ( and presumably more >expensive ) models that supports baud rates over 115.2kbaud, and you have >a 16550A or better UART on your serial port, the TA still has sync<->async The BSPro is the most commonly used external TA in the USA. It may not be the _best_ external (I still like Adtran :-) but it's popular. >PPP conversion to deal with ( start/stop bits are already 20% overhead ), >plus per-character interrupts instead of packets at a time ( OK, so the FIFO >comes in handy, but still ). > >If your ISDN equipment does Stac compression in hardware on both ends like >my Ascend, then you have even more of a data rate to support over async serial. So you need to turn the baud rate up to 230Kbps.... This will take care of the 20% bit overhead. The _right_ way to do 128Kbps on an external device (without spending the extra $400-$800 for a router) is to put the TA in 128K synchronous mode, buy a sync serial card, and do all the PPP/compression work in the PC. Unfortunately, Sync. serial cards for PC's are rare, and expensive. -- David Richards Ripco, since Nineteen-Eighty-Three My opinions are my own, Public Access in Chicago But they are available for rental Shell/SLIP/PPP/UUCP/ISDN/Leased dr@ripco.com (773) 665-0065 !Free Usenet/E-Mail!