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From: Karl Wiebe <karl@dnai.com>
Newsgroups: comp.dcom.isdn,comp.unix.bsd.freebsd.misc
Subject: Re: ISDN TA's supported for BSD Unix?
Date: 3 Feb 1997 18:54:50 GMT
Organization: DNAI ( Direct Network Access )
Lines: 25
Message-ID: <5d5c9q$eq6@jupiter.dnai.com>
References: <dkulp-ya023380000102971144510001@darkstar.ucsc.edu> <5d0nq3$7m2@news-2.csn.net> <5d2goc$fvp@grobbebol.grobbebol>
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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
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.
--Karl
--
== Karl Wiebe == karl@dnai.com ==
"Order is a form of repetition compulsion" --Freud
"Order is a form of repetition compulsion" --Freud
"Order is a form of repetition compulsion" --Freud