Is my modem UART 16450 or UART 16550 ?

Is my modem UART 16450 or UART 16550 ?

Post by Zhiyun X » Wed, 21 Sep 1994 01:22:16



I have a Internal 2400/9600 Data/Fax modem. I installed
Linux operating system. The operating system detected my
modem as UART 16450, while the seller (Compaq company) tell
me the modem is UART 16550. I confused.

Should I change the setting to UART 16550 using setserial ?
Any commends ?

Thanks all

Zhiyun Xie
------

 
 
 

Is my modem UART 16450 or UART 16550 ?

Post by Randy Hootm » Fri, 23 Sep 1994 15:28:15


Believe the data sheets that come with the computer. If Compaq says it is
a 16550 then use setserial.

Randy

: I have a Internal 2400/9600 Data/Fax modem. I installed
: Linux operating system. The operating system detected my
: modem as UART 16450, while the seller (Compaq company) tell
: me the modem is UART 16550. I confused.

: Should I change the setting to UART 16550 using setserial ?
: Any commends ?

: Thanks all

: Zhiyun Xie
: ------

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Is my modem UART 16450 or UART 16550 ?

Post by Timothy Murp » Sat, 24 Sep 1994 02:25:34


Just as an aside, does it really matter?
I've got a 16450.
Would it improve anything to get a 16550?
I have a ZyXEL with _nominally_ connects at 38400.
Transfer rate actually reaches about 1kB/sec.

I get a timeout about every 100 packets,
whenever Linux syncs, I think.

--
Timothy Murphy  

tel: +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

 
 
 

Is my modem UART 16450 or UART 16550 ?

Post by Stephen Soghoi » Sun, 25 Sep 1994 06:58:44


16550 UARTS

Hi There
I have an Intel 14,400 internal fax modem. The manual says it has
a 16550 UART. When Linux boots up it says the (modem) port has
a 16550.

So I think if your modem has a 16550 , Linux would detect it.
I cant imagine why someone would have spent the extra money
to have manufactured a 2400 baud data modem with a 16550.
Bet Compaq is pulling your leg
cheers
stephen

--
Stephen Soghoian
American Journalist - London, England

 
 
 

Is my modem UART 16450 or UART 16550 ?

Post by Matthew Dill » Sun, 25 Sep 1994 09:05:34



:>Just as an aside, does it really matter?
:>I've got a 16450.
:>Would it improve anything to get a 16550?
:>I have a ZyXEL with _nominally_ connects at 38400.
:>Transfer rate actually reaches about 1kB/sec.
:>
:>I get a timeout about every 100 packets,
:>whenever Linux syncs, I think.
:>
:>--
:>Timothy Murphy  

:>tel: +353-1-2842366
:>s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

    The answer is: yes!

    With a 16450 you cannot go faster then 19200 bps reliably.  This means
    that at 38400 you will get an occasional overrun.  The problem becomes
    much worse if you have IDE hard disks.

    With a 16550 you can go at 115Kbps easy.  

    As far as your ZyXEL goes, you can go at 57600 or 76800 (depending on
    the model and rom rev).  What this gets you is lower latency, especially
    if you are running SLIP or PPP, because whole packets must be fully
    received before a host can act upon them.

                                        -Matt

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    [always include a portion of the original email in any response!]

 
 
 

Is my modem UART 16450 or UART 16550 ?

Post by Paul Medca » Tue, 27 Sep 1994 17:23:41


:     With a 16550 you can go at 115Kbps easy.  

On a related theme...

I have a 16550A based board (according to setserial.  However, when I use
dip to connect to a remote system, despite having specified speed as 115200
the system still connects at 38400.  Modem is multitech zdx capable of
115200.  Ideas ?

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Is my modem UART 16450 or UART 16550 ?

Post by Richard Sto » Wed, 28 Sep 1994 15:15:07


: I have a 16550A based board (according to setserial.  However, when I use
: dip to connect to a remote system, despite having specified speed as 115200
: the system still connects at 38400.  Modem is multitech zdx capable of
: 115200.  Ideas ?
If you've used setserial before invoking dip, your connection is at 115200 -
dip simply reports it as 38400, since it doesn't understand anything higher.
setserial is basically a spoofer that says "anytime you receive a request
for 38400, use 57600, 115200, whatever").

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The Engineering Design Group
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1. IO Card UARTS 16550 vs 16450??

..

Not true.  Consider the limit to be 56kbps for the 16450's,
and 115kbps for most 16550A cards.  To actually use a 16450 at 56kbps
in a system with IDE disk drives, you need to use "hdparm -u1 /dev/hda" ...
to avoid dropping characters during disk I/O.  Works great.
--

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