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Setting 16550A serial port to 230,400 bps.

jlilley
jlilley asked
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Last Modified: 2011-04-14
I have an x86-based Linux box with 16550A serial ports (it is a fairly new machine).  Or at least setserial claims that they are 16550A's.  My OS is RedHat 4.2.  I'm using PPP 2.2.I'm trying to connect to my extern ISDN modem (AdTran XRT) at 230.4k.  The modem end is easy -- just a DIP switch.  But I cannot chant the right incantation to make Linux set the serial port to 230k.  I've tried putting things like this in rc.local and/or the ifup-pp script:    setserial /dev/cua0 baud_base 230400 divisor 1 spd_custWhen I do that (and set the modem for 230k), they do not talk anymore.  Does anyone know the right formula?
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Commented:
As far as I know - a 16550A can't be set to 230.4K. I have the same problem, and ended up getting a 16650 card from ByteRunner for about $25. This has a jumper so the card tells the system it's 115.2K but talks to the modem at 230.4K. This works very well - I see roughly 16-17Kbytes per second on ftp's.

Try www.byterunner.com for more info.

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Commented:
Well, it's not the answer I wanted to hear, but $25 is cheap!

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Commented:
Just contacted ByteRunner...  $20 for the card, $4 for shipping.  Card runs at 480kbps.  Cool!
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