How to Set serial port multi-user card in Linux

Article Title: how to set serial port multi-user card in Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
OS: RedHat 6.1
　　
Hardware: serial port multi-user card
Serial Port multi-user cards are generally available with jumpers (read the manual ).
I set the jumper for an eight-port multi-user card:
IRQ = 3
I/O = 0190,0198, 01a0, 01a8, 01b0, 01b8, 01c0, 01c8 (hexadecimal) eight I/O Ports
　　
Chip types of multi-user cards: 16550A/* different chip types of multi-user cards may be different */
　　
Process: The following operations are performed by the root user due to settings.
　　
　　 1. Because the interruption of the multi-use card is 3, delete ttyS1 (COM1) and ttyS3 (COM4 ).
1. # cd/dev
2. #./MAKEDEV-d ttyS1
3. #./MAKEDEV-d ttyS3
　　
　　 Ii. Generate a serial device.
1. # cd/dev
2. #./MAKEDEV ttyS11
3. #./MAKEDEV ttyS12
4. #./MAKEDEV ttyS13
5. #./MAKEDEV ttyS14
6. #./MAKEDEV ttyS15
7. #./MAKEDEV ttyS16
8. #./MAKEDEV ttyS17
9. #./MAKEDEV ttyS18
/* It is my preference to select such a serial device. You can select a serial device in the range of ttyS [0 .. 63 */
　　
　　 3. Set the serial port of the serial port device corresponding to the multi-user card
1. #/bin/setserial/dev/ttyS11 port 0x0190 irq 3 uart 16550A
/* Set/dev/ttyS11i to the first serial port corresponding to the multi-user card. The following is the example */
/* If you do not have the setserial tool, install it. RH6.1 by default */
2. #/bin/setserial/dev/ttyS12 port 0x0198 irq 3 uart 16550A
3. #/bin/setserial/dev/ttyS13 port 0x01a0 irq 3 uart 16550A
4. #/bin/setserial/dev/ttyS14 port 0x01a8 irq 3 uart 16550A
5. #/bin/setserial/dev/ttyS15 port 0x01b0 irq 3 uart 16550A
6. #/bin/setserial/dev/ttyS16 port 0x01b8 irq 3 uart 16550A
7. #/bin/setserial/dev/ttyS17 port 0x01c0 irq 3 uart 16550A
8. #/bin/setserial/dev/ttyS18 port 0x01c8 irq 3 uart 16550A
　　
　　 4. Compile the/etc/inittab File
1. Add the following lines to the/etc/inittab file:
11: 2345: respawn:/sbin/mingetty ttyS11
12: 2345: respawn:/sbin/mingetty ttyS12
13: 2345: respawn:/sbin/mingetty ttyS13
14: 2345: respawn:/sbin/mingetty ttyS14
15: 2345: respawn:/sbin/mingetty ttyS15
16: 2345: respawn:/sbin/mingetty ttyS16
17: 2345: respawn:/sbin/mingetty ttyS17
18: 2345: respawn:/sbin/mingetty ttyS18
/* The number starting with each line (such as 11) depends on your machine settings */
2. # init q/* Make the preceding added rows take effect */
Now, you have completed the configuration of multiple user cards in the serial port. Connect to the terminal and you will be able to see the long-awaited login status!
　　
In addition, if you want to use the serial port card every time you open the host, you can compile the third step into a shell file and place it in/etc/rc. d/init. d, and then in/etc/rc. d/rc3.d create a soft connection. The procedure is as follows:
1. # cd/etc/rc. d/init. d
2. # vi ttyS // the file name is selected with you
Add the following lines in step 3:
/Bin/setserial/dev/ttyS11 port 0x0190 irq 3 uart 16550A
/Bin/setserial/dev/ttyS12 port 0x0198 irq 3 uart 16550A
/Bin/setserial/dev/ttyS13 port 0x01a0 irq 3 uart 16550A
/Bin/setserial/dev/ttyS14 port 0x01a8 irq 3 uart 16550A
/Bin/setserial/dev/ttyS15 port 0x01b0 irq 3 uart 16550A
/Bin/setserial/dev/ttyS16 port 0x01b8 irq 3 uart 16550A
/Bin/setserial/dev/ttyS17 port 0x01c0 irq 3 uart 16550A
/Bin/setserial/dev/ttyS18 port 0x01c8 irq 3 uart 16550A
Save disk and exit
3. # chmod + x ttyS/* Make ttyS executable */
4. # cd/etc/rc. d/rc3.d // This is the multi-user mode that enters the character state. If the multi-user mode is enabled on the host, select the path/etc/rc. d/rc5.d
5. # ln-s ../init. d/ttyS S99ttyS // You can select another connection file name
　　
// The above is my practice. Of course many people add the above setserial content to/etc/rc. d/rc. local
.
　　
　　
If you want to know which serial port device you are using, you can edit/etc/rc. d/rc. local and add (\ l) in its line ):
1. # vi/etc/rc. d/rc. local
Find a row:
Echo "Kernel $ (uname-r) on $ a $ SMP $ (uname-m)">/etc/issue
Add (\ l) and the previous line is changed:
Echo "Kernel $ (uname-r) on $ a $ SMP $ (uname-m) (\ l)">/etc/issue, you can see the login status like this on the terminal:
......................
...... (TtyS11)
　　
... Login: