RS232-Serial communication Protocol

INTRODUCTION: RS232-Serial communication Protocol

In telecommunications, the process of sending data sequentially through a computer bus is called serial communication, which means that the data will be transmitted bit by bit. During parallel communication, data is transmitted in one byte (8 bits) or characters on multiple data lines or buses simultaneously. Serial communication is slower than parallel communication, but is used for long-term data transmission due to reduced costs and practical reasons. The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600 Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

Serial communication

Serial communication

Parallel communication

Parallel communication

Data transfer mode in serial communication:

Asynchronous Data Transfer – The way in which data bits are not synchronized by a clock pulse. The clock pulse is a signal used to synchronize operation in an electronic system.

Synchronous Data Transfer – How the data bits are synchronized by a clock pulse.

Serial communication features:

The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600.

Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

What is RS232?

RS232C “Recommended 232C standard” is the recent version of the 25-pin standard, while RS232D is 22-pin. In the new 9-pin male D-type PC.

RS232 is a standard protocol used for serial communication The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600, it is used to connect the computer and its peripherals to allow the exchange of serial data between them. As you get the strain on the path used for data exchange between devices. It is used in serial communications up to 50 feet with a speed of 1,492 kbps. As defined by EIA, RS232 is used to connect data transmission equipment (DTE) and data communication equipment (DCE). Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

RS232 protocol
RS232 protocol

RS232 protocol

Universal asynchronous data receiver and transmitter (UART) used in connection with RS232 to transfer data between the printer and the computer. The microcontrollers are not able to manage these types of voltage levels, the connectors are connected between RS232 signals. These connectors are known as a DB-9 connector as a serial port and are of two types: male connector (DTE) and female connector (DCE).\

electrical specifications

We discuss the RS232 electrical specifications below:

Voltage levels: RS232 is also used as a ground level and 5V. Track 0 works with voltages up to + 5 V at + 15 V DC. It’s called “ON” or spacing (high voltage level), while Binary 1 works with voltages ranging from -5 V to -15 V DC. It is called “OFF” or marked (low voltage level).

Voltage level of the received signal: binary 0 works with signal voltages received up to +3 V at +13 Vdc and Track 1 works with voltages up to -3 V at -13 V DC.

Line impedances: the impedance of the cables goes from 3 ohm to 7 ohm and the maximum cable length is 15 meters, but new maximum length in terms of capacity per unit of length.

Operating voltage: the operating voltage will be 250 VAC max.

Rated current: the rated current will be 3 amps max.

Dielectric withstand voltage: 1000 V AC min.

Response rate: the rate of change in signal levels is called the response rate. With its response speed it is up to 30 V / microseconds and the maximum bit rate will be 20 kbps.

RS232 works in bidirectional communication which exchanges data between them. There are two devices connected together, (DTE) Data Transmission Equipment and (DCE) Data Communication Equipment which has pins such as TXD, RXD and RTS & CTS. Now, from the DTE source, the RTS generates the request to send the data. The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600 So on the other hand, the DCE, the CTS, paves the way for data reception. After clearing a route, it will report the RTS from the DTE source to send the signal. The bits are then transmitted from DTE to DCE. Now again from the DCE source, the request can be generated by RTS and CTS from DTE sources clarifies how to receive the data and gives a signal to send the data. This is the whole process by which data Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

transmission occurs.

TXD TRANSMITTER

RECEIVER RXD

RTS SEND REQUEST

CLEAR CTS TO SEND

EARTH TO EARTH

Mechanical specifications

For the mechanical specifications, we have to study two types of connectors which are DB-25 and DB-9. In DB-25, 25 pins are available which are used for many applications, but some applications have not used the full 25 pins. Therefore, the 9-pin connector is made for the convenience of devices and equipment The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600.

Now, here we are discussing the DB-9 pin connector which is used for the connection between microcontrollers and connector. These are of two types: male connector (DTE) and female connector (DCE). There are 5 pins on the top row and 4 pins on the bottom row. It is often called the DE-9 or D-type connector. The baud rate is used to measure the baud rate. It is described as the number of bits that pass in a second. For example, if the transmission rate is 200, 200 bits are passed per second. On the telephone lines, the transmission speeds will be 14400, 28800 and 33600 Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

RS232 or DB9 male connector c

Pin structure of the DB-9 connector:

RS232 or DB9 female connector

Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

PIN No.Pin NamePin Description
1CD (Carrier Detect)Incoming signal from DCE
2RD (Receive Data)Receives incoming data from DTE
3TD (Transmit Data)Send outgoing data to DCE
4DTR (Data Terminal Ready)Outgoing handshaking signal
5GND (Signal ground)Common reference voltage
6DSR (Data Set Ready)Incoming handshaking signal
7RTS (Request to Send)Outgoing signal for controlling flow
8CTS (Clear to Send)Incoming signal for controlling flow
9RI (Ring Indicator)Incoming signal from DCE

In RS 232, the term RS means recommended defamation and the number 232 specifies the latest version. There are several types of serial communication systems designed to transfer information over long distances through a variety of information cables. generates the request to send the data. So on the other hand, the DCE, the CTS, paves the way for data reception. After clearing a route, it will report the RTS from the DTE source to send the signal. The bits are then transmitted from DTE to DCE. Now again from the DCE source, the request can be generated by RTS and CTS from DTE sources clarifies how to receive the data and gives a signal to send the data. This is the whole process by which data transmission occurs. Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

The term serial refers more often to the RS232 port which is called the serial port, and therefore to the various devices designed to be compatible with it using a serial cable connected to it. Basically, all long distance communications transfer information one bit at a time, rather than in parallel, consequently reducing the price of the cable. In telecommunications, this RS232 port is a standard serial communication data transmission. It formally describes the signals connected between a data terminal equipment (DTE) and a data circuit termination equipment (DCE). Here, DTE is a computer terminal and DCE is a modem. This article provides brief information on the basics of RS232 communication. Stop bits are used for a single packet to stop transmission, indicated by “T”. Some typical values ​​are 1, 1.5 and 2 bits.

Parity Bit is the easiest way to check for errors. There are four types, namely odd, marked and spaced. For example, if 011 is a number, the parity bit = 0, or even parity and parity = 1, or odd parity.

Applications

RS232 serial communication is used in older generation PCs to connect peripherals such as mouse, printer, modem, etc.

Today RS232 is replaced by advanced USB.

It is also used in PLC machines, CNC machines and servo controllers because it is much cheaper.

It is still used by some microcontroller cards, receipt printers, point of sale systems (PoS), etc.

Leave a comment

You must be logged in to post a comment.