Date: Mon, 24 Jul 1995 03:41:49 +0400 (MSD) From: =?KOI8-R?Q?=E1=CE=C4=D2=C5=CA_=FE=C5=D2=CE=CF=D7?= aka "Andrey A. Chernov, Black Mage" <ache@astral.msk.su> To: bde@zeta.org.AU, terry@cs.weber.edu Cc: hackers@freebsd.org, harry@hgac.com, jkh@violet.berkeley.edu Subject: Re: dial up at > 9600 baud Message-ID: <gVzuj4mmn7@astral.msk.su> In-Reply-To: <199507232218.IAA23750@godzilla.zeta.org.au>; from Bruce Evans at Mon, 24 Jul 1995 08:18:28 %2B1000 References: <199507232218.IAA23750@godzilla.zeta.org.au>
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In message <199507232218.IAA23750@godzilla.zeta.org.au> Bruce Evans
writes:
>>Ok, I finaly understand what you say now :-)
>>So, described situation is possible, only when some dialout application
>>previously send chars at different speed and modem remember
>>last speed. So, my comhardclose() fix with comparam(com->it_in)
>>isn't enough, because driver need to send AAAT\r command to modem
>>after it additionly :-(
>It might be enough to send a single character while carrier is down
>The modem has to determine the speed before it can read an `A' :-).
>Are your extra A's to help it do this?.
Some modem can determine before, some not.
Some modem determine speed only when AT-command issued, not for
any char.
Just experimenting with Microcom: 3 A always enough
to determine changed speed (A appearse), 2 A is enough in 90% cases,
>What determines the speed
>after the following sequence:
> 1) turn on modem
> 2) open port (don't write)
> 3) wait for carrier
> 4) write to port ?
It depends on what modem does on power on, if it does ATZ
it will be ATZ-configured speed, or last speed in other case.
>The Linux driver has (had?) some optional support to help getty handle
>this. After the last close of cuaa, sleeping opens of ttyd return
>EAGAIN. This gives getty a chance to send the AT command.
Does EAGAIN allowed on open by POSIX?
>>So, any dialout program which change serial speed becomes
>>getty-killer. We need to document locked devices to getty/gettytab
>>manpage too as mandatory to not allow speed changes.
>The modem is supposed to reset itself when DTR is dropped. We
>don't document this but it should be the hardware default. It
It isn't default modem setting in 100% modems which I see.
We should document it somewhere among with disabling CONNECT
string in answering mode.
--
Andrey A. Chernov : And I rest so composedly, /Now, in my bed,
ache@astral.msk.su : That any beholder /Might fancy me dead -
FidoNet: 2:5020/230.3 : Might start at beholding me, /Thinking me dead.
RELCOM Team,FreeBSD Team : E.A.Poe From "For Annie" 1849
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