Mailinglist Archive: opensuse (4547 mails)

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Re: [SLE] Still cant connect to my ISP
  • From: "Carlos E. R." <robin1.listas@xxxxxxxxxx>
  • Date: Mon, 3 May 2004 02:25:18 +0200 (CEST)
  • Message-id: <Pine.LNX.4.53.0405030150570.13538@xxxxxxxxxxxxxxxx>

The Sunday 2004-05-02 at 16:36 +1000, Basil Chupin wrote:

> It is physically not possible to connect on a dial-up connection above
> 57600 baud - nor can data flow faster than the theoretical 57600 baud
> simply because this is the upper limit of the beast.

I know. I work(ed) in that field. :-)

However, as I said, there are two serial connections involved with a
modem, and the first one, from computer to modem, can be quite higher, and
is in fact recommended to be higher. For example, this is my configuration:

nimrodel:~ # setserial -a /dev/modem
/dev/modem, Line 1, UART: 16550A, Port: 0x02f8, IRQ: 3
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

And I can assure you it works. The actual connection speed (local modem to
exchange router (modem)) was reported the last time as:

ATDT908200290
CONNECT 50666/ARQ/V90/LAPM/V42BIS

>
> A connect speed of 115200 simply indicates that the settings are wrong
> and the modem is reporting the DCE speed and not the actual connect
> speed of the 2 modems.

Not necessarily wrong: it is simply reporting the speed of the serial port
from the computer to the local modem, which is not useful - but not
necessarily wrong.


> The compression you mention above can only apply to data which can
> actually be compressed, but even if it is compressed it can still only
> get transmitted at the theoretical upper limit of 57600 bps; and being
> compressed it *appears* that it is being transmitted quicker.

More or less :-)

The speed on the line, is of course, limited to the connection speed
(bytes per second). However, the observed dataflow speed by the system can
be higher if, as you say, the data can be compressed - for example, normal
mail can -. For this to work, however, the serial port of the computer has
to be higher than the modem to modem connect speed.


--
Cheers,
Carlos Robinson

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