minicom.faq

minicom的源码,linux下常用的串口程序.

$Id: minicom.FAQ,v 1.1.1.1 2003/03/30 18:55:39 al-guest Exp $

Frequently Asked Questions about Minicom:


Q1: I have a "winmodem". How can I use it with minicom?

A1: This is actually a hardware problem, not a minicom problem.
Sorry, but there is often no hope to use those things in Linux at all.
They are not actually real modems, they rely on the processor to do much
of the work that really belongs to the modem. So they need some drivers.
And many manufacturers of them are ignorant. So they write the drivers
only for windows, and don't care about people who use something better.
Not even enough to publish information that would be required to write
drivers for more decent operating systems. However, some of them DO have
the necessary drivers. The list should be available at
    http://www.linmodems.org/ 
If your "winmodem" is mentioned there as Linux-compatible, then you should
be able to use it like any real modem, once you get it installed properly.
Follow the instructions on the website.
If your device is not mentioned, it probably is not supported in Linux
at all and you should get a real modem.
As far as I know, most PCI modems (but not all) are these "winmodems".
All external modems and almost all ISA card modems are real things, and
they can be used with no problem (or if you seem to have problems with an
ISA modem responding slowly or losing characters, see the next question).


Q2: Why does my modem respond so SLOWLY to everything I type? Even the init
string seems to pause for seconds between each character.

A2: This is another hardware problem.  
You have an interrupt conflict in your computer. That means, some other
device is using the same IRQ as your modem. This happens quite often if you
have an internal modem set up as /dev/ttyS2 or /dev/ttyS3 (also known as
com3 or com4 on some other operating systems). By default, /dev/ttyS0 and
/dev/ttyS2 (or com1 and com3) use IRQ 4 and /dev/ttyS1 and /dev/ttyS3 (or
com2 and com4) use IRQ 3. So, if you have an internal modem, disable the
serial port using the same irq on your motherboard or i/o card (check the
motherboard manual), or change one of the ports to use some other irq
(probably with the setserial command in /etc/rc.d/rc.local or some other
bootup script).


Q3: When I try dialing out, minicom just says "you are already online" and
refuses to dial. Why does it do that and what should I do?

A3: Since version 1.82, Minicom doesn't begin dialing if the modem says that
you are online by keeping the carrier signal on.
Maybe your modem always keeps the carrier signal on. Consult the manual of
your modem for the right command to use the carrier signal properly.
On my modem, the command would be at&c1 but it may be different in your
modem. Save the changed modem settings or add &c1 (or whatever it is) to
your init string. 
If your modem is broken and can't handle the carrier signal, you may set
minicom to ignore DCD by going to the "modem and dialing" settings and
turning off the "Modem has DCD line" setting.