rs 232c serial port

Introduction to serial port standard for RS-232, RS-422 and RS-485 1. The origin of RS-232C, RS-422 and

Point:1. Serial Port and comport are physical interfaces (hardware ). While TTL, RS-232, RS-485 refers to the level standard (electrical signal ). 2. Generally, only Gnd RX Tx is connected to the device. Do not connect to the VCC or + 3.3v power cord to avoid power supply conflicts with the target device. 3. The pl2303

) ③ 6 blank) ④ One protected area (PE), used as the grounding end of the equipment (foot) Note: The 20mA current ring signal is only provided by ibm pc and ibm pc/XT machines. It is not supported by AT machines or later ｡ DB-9 connectors (2) AT machine and later, do not support 20mA current ring interface, use DB-9 connector, serves as a connector that provides both a multi-functional I/O card or a COM1 and COM2 serial interfaces on the motherboard. I

equipment (foot) Note: The 20mA current ring signal is only provided by ibm pc and ibm pc/XT machines. It is not supported by AT machines or later ｡ DB-9 connectors (2) AT machine and later, do not support 20mA current ring interface, use DB-9 connector, serves as a connector that provides both a multi-functional I/O card or a COM1 and COM2 serial interfaces on the motherboard. It provides only nine signals for asynchronous communication. DB-25 Conne

(including signal ground SG) of asynchronous communication are 2, 3, 4, 5, 6, 7, 8, 20, 22 ② 20mA current ring signal 9) ③ 6 blank) ④ One protected area (PE), used as the grounding end of the equipment (foot) Note: The 20mA current ring signal is only provided by ibm pc and ibm pc/XT machines. It is not supported by AT machines or later ｡ DB-9 connectors (2) AT machine and later, do not support 20mA current ring interface, use DB-9 connector, serves as a connector that provides both a multi-fun

) make the RLSD signal effective when the MODEM sends the carrier signal, notify the terminal to prepare for receiving, and after the MODEM decrypts the received carrier signal into digital data, this line is also called the Data Carrier dectection-DCD line ｡ Ringing-RI-when the MODEM receives the Ringing call signal sent by the switching station, make the signal valid (ON status), the notification terminal, has been called ｡ RS-

RS-232C interface definition (DB9) PIN definition symbols 1 Carrier Detection DCD (data carrier detect) 2 receive data rxd (received data) 3 send data txd (transmit data) 4 data terminal prepare DTR (Data Terminal ready) 5 signal SG (signal ground) 6 data prepare DSR (data set ready) 7 request to send RTS (request to send) 8. Clear send CTS (clear to send) 9. The ring indicator prompt is Ri (ring indicator)

time to read the first character Turning off terminal Echo, the characters entered by the keyboard are not displayed in the terminal window. #include serial port itself, standard and hardware † The serial port is the physical interface of serial communication on th

The article starts at the vast first Sen blog1. Get the serial numberIn the Linux system everything is a file, so the serial port number is no exception, are in the form of device files. This means that we can access them using commands that access the text files.A. The general serial

boot. That's the first thing we're going to change.If you look at the files in the/etc/init directory, you will find some existing Terminal Services configuration files, such as tty1.conf. Very simply, we can copy one of the files:CP /etc/init/tty1.conf/etc/init/ttys0.confThen we modify the new ttys0.conf:Will: # Tty1-getty Switch # Ttys0-getty Will: # This service maintains a Getty in tty1 from the point of the system is Switch # This service

This article mainly provides a practical Java serial communication program for discussion and learning. /*************************************** **** Program file name: sendcomm. Java* Function: send data from the serial port COM1**************************************** **/Import java. AWT .*;Import java. AWT. event .*;Import java. Io .*;Import java. util .*;Imp

of the check digit "1" should be even. When the character is received, the number of "1" is checked, if inconsistencies are found, there is a mistake in the process of transmitting data.Code and Checksum: the sender sums (or each byte xor) the data block that is being sent, producing a check character (checksum) of one byte appended to the end of the data block. The receiver receives the data at the same time the data block (except check byte) sum (or each byte xor), the result is compared with

is, one-bit and one-bit transmission. We often say that the serial port refers to the RS-232C interface, which was in 1970 by the American Electronics Industry Association (EIA) the serial communication standard jointly developed by Bell systems, modem manufacturers, and co

From https://www.ibm.com/developerworks/cn/linux/l-serials/ Introduction to serial ports The serial port is a common interface for computers. It has a wide range of applications, such as a few connection lines and simple communication. Commonly used serial port is

class library. This is a Java Extension class library that is not included in the standard Java SDK. If you haven't installed the Extended class library, you should download the library from Sun's Java site and install it on your system. In the download package contains an installation instructions, if you do not properly install the class library and its operating environment, you can run this program when you will not find the serial

1 logic level EIA-RS-232C of electrical properties, logic and various signal line functions are defined. On txd and rxd: Logic 1 (Mark) =-3v ~ -15 V Logic 0 (Space) = + 3 ~ + 15 V On the control line such as RTS, CTS, DSR, DTR, and DCD: Effective Signal (on, positive voltage) = + 3v ~ + 15 V Invalid signal (disconnected, off, negative voltage) =-3v ~ -15 V 2. Pin Definition Pin definiti

When we learn the principles of the microcomputer, many people will have a big problem with some interface bus. These are some of the content contained in the serial port protocol. So in order to better understand some interface serial port protocol standards, we will give a detailed introduction to such problems.

Original address: http://www.cnblogs.com/feisky/archive/2009/10/23/1588771.html Linux operating system from the beginning of the serial port provides a good support, this article on Linux under the serial port communication programming simple introduction. Introduction of

RS-232, RS-422 and RS-485 standards only to interface electrical characteristics to make provisions, and does not involve connectors, cables or protocols, on this basis, users can establish their own high-level communication protocols. The most frequently used plug-ins we encounter in our actual work have three DB9 DB25 RJ45 plug-ins. The above three plug-ins ca

: Parallel Communication PortParallelportevent parallel port eventSerialPort RS-232 serial communication portSerialportevent serial port event Three exception classesNosuchportexception thrown when the driver cannot find the specified portPortinuseexception thrown when a spe