getty?
getty is a program that handles the login process when you log
onto a Unix box. You will need to use getty if you want to be
able to dial in to your Linux machine with a modem. You do not need
to use getty if you only want to dial out with your modem. There
are three versions that are commonly used with Linux: getty_ps,
mgetty and agetty. The syntax for these programs differs,
so be sure to check and make sure that you are using the correct syntax for whatever getty you use.
getty_ps
Most distributions come with the getty_ps package installed.
(Debian used agetty but now uses mgetty.) It contains two programs:
getty is used for console and terminal devices, and uugetty
for modems. I use this version of getty, so that is what I will
focus on.
mgettymgetty is a version of getty mainly for use with modems. It
may be used for hard-wired terminals but the documentation is about
99% related to modems. In addition to allowing dialup logins,
mgetty also provides FAX support and auto PPP detection. The
mgetty documentation (supplied in texinfo format) is good, and
does not need supplementing. Please refer to it for installation
instructions. You can find the latest information on mgetty at
http://www.leo.org/~doering/mgetty/.
agettyagetty is the third variation of getty. It's a simple,
completely functional implementation of getty which is best
suited for virtual consoles or terminals rather than modems.
setserial?
setserial is a program which allows you to look at and change
various attributes of a serial device, including its port address,
its interrupt, and other serial port options. You can find out what
version you have by running setserial with no arguments. If the
argument is /dev/ttyS1, etc., then you'll see some info about that
port.
When your Linux system boots, only ttyS{0-3} are configured,
using the default IRQs of 4 and 3. So, if you have any other serial
ports provided by other boards or if ttyS{0-3} have a non-standard
IRQ, you must use setserial in order to configure those serial
ports. For the full listing of options, consult the man page.