Of course, the best way to communicate between two computers is to establish a local area network. If the network is not established,
If you want to communicate online, if the distance is not too far (for example, no more than 20 meters), you can consider merging by computer.
The line port or RS-232 serial port directly connects two machines, thus realizing communication, data and file transmission, software and hardware.
Enjoy the resources. The port is used to connect two computers for data transmission, without network card, modem and so on.
Floppy disk is a simple and good communication and data transmission method. What is particularly commendable is that it can be implemented.
At present, the software and hardware resources between two computers are shared, such as hard disk, CD-ROM drive, printer, etc.
For point-to-point communication between two microcomputers, the parallel port or serial port should be connected by connecting cable in hardware, and then the communication software should be used.
Only with the support of a piece can it be realized. This paper discusses the connection method of signal line, the making of connecting line and communication software.
This paper introduces the realization technology of point-to-point communication between two microcomputers without network card.
First, the signal line connection method
Microcomputer usually has a parallel port and two standard RS-232 serial ports. We can choose any one of them.
Communicate between two machines. If possible, we should use parallel port for communication, because the transmission rate of parallel port is much higher.
Yu serial port.
Serial port 1(COM 1) is mostly 9-core, and serial port 2(COM2) and parallel port are 25-core pins. It is correct that each port pin has a different function.
The connection is also different.
1. serial communication
The communication between serial ports only needs to connect three wires, namely, receiving and sending data wire and information ground wire. At the time of connection, right
One machine is sending data and the other machine is receiving data, so the receiving and sending data lines should be switched. Serial port chamber
There are three ways to connect communication.
(1)9-core to 9-core serial port
Machine a and machine b
2●←→●3
3●←→●2
5●←→●5
(2)9-core (machine A) to 25-core (machine B) serial port
Machine a and machine b
2●←→●3
3●←→●2
5●←→●7
(3)25-core serial port to 25-core serial port
Machine a and machine b
2●←→●3
3●←→●2
7●←→●7
2. Parallel port communication
The parallel port pin has only five input lines, such as 10,1,12, 13, 15, etc. , so when communicating with two computers, it is also
Only five output lines can be used, so the connection method of two parallel port communications is as follows.
The numbers listed above are the pin numbers of connectors, which are usually displayed on serial and parallel ports. pass by
Parallel port uses 5 pairs of wires to transmit data, which is much faster than serial communication, so it should be used as much as possible.
Parallel port connection, especially when a large amount of data needs to be transmitted between two computers.
Second, the production of connecting wires
The cable connecting the two machines can be bought in the computer accessories store. Make sure that both parties are clear when buying.
Are connectors pins or holes? Usually, 25 pins are used to connect two parallel ports, while holes are used to connect two serial ports.
Yes
You can also make your own connection lines. No matter whether the socket on the computer is a pin or a hole, it is connected directly with a wire.
More difficult, resulting in poor interface contact. Here we recommend two methods of serial port connection by using the cable of waste mouse.
Circuit and method for making parallel connection wire by using waste printer cable.
1. Make 9-core serial connection cable.
The mouse only uses four of the nine pins of the serial port, namely pins 2, 3, 5 and 7. When using serial communication, you only need to
Just connect pins 2, 3 and 5. The mouse is an easily damaged device, and the main damage is the mouse.
Boss, its connections and joints are generally not broken. Cut the wires of two abandoned mice, and you can find that they are out of protection.
There are four wires under the skin, the colors are brown, yellow, green and white, which correspond to needles 2, 3, 5 and 7 respectively. According to the previous introduction
In the connection method, the green line in the connecting line of two mice is butted, and the brown line and the yellow line are switched (that is, the brown line on the first side is connected to the second side).
The yellow line on the side, the yellow line on the first side and the brown line on the second side are connected), and the white line is not used. After the wires are connected, tie the connectors with tape.
Ok, a 9-hole to 9-hole serial connection line is ready. It is convenient and practical to make serial connection cable with discarded mouse connection cable.
Use, saving time and economy, is a good way to use waste.
2. Make parallel connection lines
It is also convenient to use printer cable as parallel cable. Disconnect both ends of the cable first, and then connect the printer.
One end of the thread is welded down; Then, according to the pin number and wire color at the other end of the cable, weld.
According to the parallel connection mode introduced earlier, the wires with corresponding colors are welded to the corresponding pins of the 25-core D-plug; most
Then weld the ground wire connecting the shell and the D plug. In this way, a 25-core parallel port-to-parallel port connection cable is completed.
Yes
3. Make a 25-core to 25-core serial connection cable.
To make a 25-core to 25-core serial connection cable, you need two 25-hole plugs and a second-hand mouse connection cable.
According to the color of the wire and the connection mode described above, it is enough to weld both ends of the wire on the corresponding pins.
Third, communication software
Insert both ends of the connecting cable into the corresponding serial ports of two machines respectively. Data communication cannot be carried out immediately, but there must be
Support of communication software. There are many softwares that can realize direct communication between two computers. Commonly used are the following.
Choose one from the actual situation and use it.
1. windows 95
The "Direct Cable Connection" function of Windows 95 allows direct cable connection between parallel or serial ports of two computers.
Now communicate online. The process of establishing connection and realizing communication is as follows.
(1) Install a direct cable connection on the server.
① In the ①Windows 95 desktop environment, through My Computer → Control Panel → Network, select
Dial the network adapter and select Microsoft Network Client in the Basic Network Login Mode (L) window.
② Enter my computer → Control Panel → Add/Remove programs → Install Windows"→
"Communication" → "Direct Cable Connection" and install the "Direct Cable Connection" program.
③ Confirm * * * permissions through my computer → control panel → network → document printing.
Limited, there are "Let others access my files" and "Let others print to my printer"
"On" two options.
(4) Through my computer, right-click any drive letter in this window and select "* * * Enjoy" to enter * * *.
Enjoy the level setting window, where you can set the * * * enjoy level and password, etc. If you want to enjoy other drives, you can click "Me".
Right-click another drive letter in the Computer window and set the * * * access level and password. * * * can also be set in the same way.
Enjoy this folder.
⑤ Run the direct cable connection process through Start → Program → Accessories → Direct cable connection.
Sequence, set to "host", and select COM 1 as the connection port.
In this way, a server providing * * * resources is established. For future connection, if it is not modified, only
Just run the direct cable connection program. If you want to change the connection port, change the server to a client or.
Modify the * * * enjoyment resources, and then modify the corresponding settings.
(2) Install direct cable connection on the client.
The method of installing the direct cable connection program on the client is the same as that on the server. Direct cable connection program
Run after installation, set it as "client", and select COM 1 as the connection port.
Just run the direct cable program in the future, and don't set it again unless you want to modify it.
(3) Advantages and disadvantages
The connection between the server and the client can be established by running the direct cable connection program on the server and the client respectively.
Answer the phone. If there is a password, it will also be verified when connecting. After the connection is established, the client can use the
My Network Places on the Windows 95 desktop accesses the server's * * * resources.
The main advantages of connecting two microcomputers with Windows 95 direct cable connection program are as follows: ①.
After the connection is established, the client can use the resources provided by the server, and the client and the server can also run independently.
; (2) If the connected server is connected to the local area network, the client can also access all online resources through the server.
; ③ You can * * * enjoy all the resources on the server, such as CD-ROM and network drives.
The only disadvantage of using the direct cable connection program of Windows 95 to connect two microcomputers for communication is that it is necessary for the machine.
The requirements are higher, because both the client and the server need to install Windows 95/98 to connect, while some low-end machines such as
Windows 95/98 cannot be installed and run on a machine below 386.
2.2 driving map. PCTools 9.0
PCTools 9.0 provides a practical and convenient online communication software, DRIVEMAP, which can be accessed through.
A serial port or a parallel port connects two computers and uses the empty disk symbol of one computer to image the physical disk of the other computer. We use
A machine whose drive is mapped by the drive letter of another machine is called a server, and the other drive is called by the mapped machine.
Clients. The method of online communication through DRIVEMAP is as follows.
(1) Run DRIVEMAP on the client first.
Type DRIVEMAP at the prompt of the client system (assuming that the file exists in the current directory or reference directory). if
The first time you run DRIVEMAP, the installation window of DRIVEMAP will appear, asking you to enter your user name and password. user name
Input is required to identify different connected microcomputers. The password item is optional. If you don't want the password, just press enter.
Do it. Then select the next item to enter the next level of connection equipment selection menu, and select COM 1 serial port. Then select OK to enter the settings.
Prepare to redirect the selection menu. If it is not the first time to run DRIVEMAP, directly enter the device redirection selection menu.
Press the X or Esc key to exit the DRIVEMAP installation, and the client will be ready to connect.
(2) Run DRIVEMAP on the server, and the screen display and operation are the same as installing DRIVEMAP on the client. Among the listed books
Select a drive character for the image from all used drives and unused but available drive letters. tie
If there are no empty drive characters available, use the "LASTDRIVER=" statement in the configuration file. You must modify the SYS file to make it
There is an empty drive letter in the system. Move the operation light bar of DRIVEMAP to the empty drive letter mark (assuming it is f:), and then press Enter.
Select the online port COM 1 and press Enter, and then determine which drive on another machine the F letter of this machine is connected to.
Press the O key to return to the previous window after selection, and then press the Esc (or X) key to exit the DRIVEMAP interface. Then two machines will be fine.
To communicate. Moreover, the two machines can run independently and are not affected.
(3) Advantages and disadvantages
Using DRIVEMAP in PCTools 9.0 as communication software between two computers has many outstanding advantages: ① server.
If the server environment permits, use the client's drive (including CD-ROM drive) as your own drive.
(Memory size, BIOS version, graphics card and monitor, etc. ) to mirror all executable files on the drive.
Can run; (2) After the two computers are connected, they can run independently; ③ Imageable CD.
The disadvantage of DRIVEMAP is that it can only mirror one drive of the client. To create an image of another drive of the client,
Device, you must first exit the image drive, and then reselect the drive to be imaged. In addition, to change the connection
Port, after making changes, you must restart the system to take effect.
3. Commander Norton's link
Commander Norton's link also provides online communication, as follows.
(1) Run NC in the slave.
Run NC at the system prompt, press F9 to enter the NC main menu, and select the link item on the left or right.
Select COM 1, then select the slave, move the cursor to Link and press Enter.
(2) Run NC on the host.
After the host runs NC, press F9 to enter the NC main menu, select the left or right link item, and select
COM 1, then select Master, move the cursor to Link and press enter. In this way, the two machines are connected and can be used in.
The master device accesses the data on each drive of the slave device through the left (or right) panel.
(3) Advantages and disadvantages
The advantage of using NC as communication software between two computers is that you can access the data on each driver of the slave machine and package it.
Includes an optical disc. However, it also has many disadvantages: ① During communication, the slave can't do any operation; (2) On the host, only
Using the operation commands provided on the NC panel to operate the data in the drive connected to the slave machine has limited functions; ③
You cannot run executable files or edit text files on connected disks.
INTERLNK software of 4.4. disc operating system (DOS)
The DOS version above 6.0 provides interconnection through the parallel port or serial port of the computer, thus realizing the computer.
* * * Enjoy programs between resources, which are INTERLNK and INTERSVR. The former runs on the client, and the latter runs on the client.
Run on the server. It must be in the configuration file, whether on the client side or the server side. SYS file.
Add command line: device = c: \ dos \ interlnk.exe. The steps to establish a connection between a client and a server are as follows.
(1) Type the INTERSVR command at the system prompt of the computer used as the server.
(2) When the server is running INTERSVR, type at the system prompt of the machine used as the client.
INTERLNK command, the screen shows the empty drive letter of this machine (client) and the actual drive letter of another machine (server).
Image relationship. After that, you can use the empty drive letter of the client to operate the actual drive of the server.
(3) Advantages and disadvantages
The outstanding advantage of connecting and communicating between two computers by using the INTERLNK software of DOS is that it can be used at the client.
Mirror multiple drives on the server with multiple drive letters, and INTERLNK will automatically identify the location without setting a connection port.
The connected port. Its disadvantages are as follows: ① During the online period, the server cannot do any other work; ② Can't reflect.
Such as network drives and optical disks.
Docking of twisted pair
The last issue of "Client Network Card Experimental Report" mentioned the docking mode of twisted pair, and now it is aimed at NO.
Explain it by the same standard.
I. Overview of 10BASE-T, 100BASE-TX and 100BASE-T4 standards.
10BASE-T stipulates that three types of unshielded twisted pair (UTP) are used to form a 10M network, and each network segment can at most
Reach communication distance 100 meter; 100BASE-TX specifies the use of Category 5 (CAT5) unshielded twisted pair (UTP) or 1 class shielding.
Twisted pair (STP) forms a network of 100M, and each network segment can reach the communication distance of 100m at most; 100BASE-T4 regulation
Using unshielded twisted-pair cables of Class 3, 4 or 5 to build a 100M network, each network segment can reach a communication distance of 100m at most.
See table 1 for the definition of each pin in these three standards.
Pin10base-t100base-tx100base-t4
serial number
1 Send (+) Send (+) Send (+)
2 Send (-) Send (-) Send (-)
3 Receive (+) Receive (+) Receive (+)
4 empty bidirectional data line 1(+)
5 null bidirectional data line 1(-)
6 Receive (-) Receive (-) Receive (-)
7 null bidirectional data line 2(+)
8 empty bidirectional data line 2(-)
Second, the docking method of twisted pair
According to the above, we can get figure 1 and figure 2. According to the diagram, you can make a dual-machine network of 10M or 100M.
Wiring in pairs. Pay attention to the direction and arrangement order of lines when making thread ends. The arrangement order of twisted pairs is from 1 to 8 respectively.
Representatives: red and white, red, brown and white, brown, green and white, green, blue and white and blue. When making, hold the thread in your left hand and the crystal head in your right hand. pay attention to
The shrapnel side of the Italian crystal head is facing down. The number of directions from the outside to oneself, the corresponding arrangement order is 1 ~ 8, that is
Line 8 is closest to you.
Many network devices don't support 100BASE-T4 standard, so most of them only use 4 wires when making 100M wire pairs.