rs232 rs422 rs485 What is the maximum distance they can transmit? Thank you

The transmission distance of RS232 needs to be within 15 meters, and there is no way to transmit the distance of 80 meters, and the short distance is one of the disadvantages of RS232.

The RS-232 also has drawbacks:

1) The signal level value of the interface is high, and the chip of the interface circuit is easy to be damaged, and because it is incompatible with the TTL level, it is necessary to use the level translation acacia circuit to connect with the TTL circuit.

2) The transmission rate is low, and the baud rate is 20kbps when asynchronous transmission; Therefore, in the CPLD development board, the integrated program baud rate can only be used at 19200, which is also the reason.

3) The interface uses a signal line and a signal return line to form a common-ground transmission form, which is easy to produce common-mode interference, so the anti-noise interference is weak.

4) The transmission distance is limited, the maximum transmission distance is 50 feet, and in fact, it can only be used for about 15 meters.

The 485 protocol and 232 transmission distances are:

Protocol: The RS-485 interface has a maximum transmission distance of 4000 feet as standard, and can actually reach 3000 meters (in addition, the RS-232-C interface only allows 1 transceiver to be connected on the bus, i.e. single-station capability.

The RS-485 interface on the bus allows up to 128 transceivers to be connected. This means that it has multi-station capability, so that users can easily set up a network of devices with a single RS-485 interface.

Protocol: RS-232 transmits at 10MB s, extends to 4000 feet (at rates below 100 kbs) and allows up to 10 receivers to be connected on a balanced bus.

RS232 is limited to 15 meters.

The theoretical transmission distance of the RS-232 protocol is 10 meters, and the theoretical transmission distance of the RS-485 protocol is 1000 meters.

The maximum transmission distance of RS485 without repeater is 1200 meters (this value can be broken by using special cables with impedance matching and low attenuation), and the maximum number of repeaters required is not more than 8, that is, 9600 meters.

The maximum communication distance of RS-232 to RS485 is 1200 meters, which only needs to buy a converter to meet this communication requirement.

RS232 can be extended within 10 meters, and 422 can be extended within 25 meters.

RS-232 is one of the most widely used serial interfaces in the PC and communications industry. RS-232 is defined as a single-ended standard that increases the distance of communication in low-rate serial calls. RS-232 uses an unbalanced transmission mode, which is called single-ended communication.

RS232 has a maximum transmission distance of 15m, a maximum transmission rate of 20kbpsRS422 485, a maximum transmission distance of 10Mbps, and a 9-pin serial cable that can support RS232 422 485.

The computer serial port (RS232) has a total of 9 pins, all of which are arranged in order, and each pin is defined as follows:

1. Definition of pin 1:

Carrier Detection (DCD), Received Line Detection (RLSD).

2. Definition of pin 2:

Accept Wild Data (RXD) is the pin to receive data.

3. Definition of pin 3:

Transmit data (txd) is the pin that sends data.

4. Definition of pin 4:

Data Endpoint Ready (DTR), an acronym for Data Endpoint Ready.

5. Definition of pin 5:

Signal ground (SG).

6. Definition of pin 6:

Data Ready (DSR), when the modem is turned on, after self-detection, is used to declare that it is ready.

7, the definition of pin 7 and slipping:

Request to Send (RTS) to get the sending information.

8. Definition of pin 8:

Clear Send (CTS) to clear the data.

9. Definition of pin 9:

Ring Indicator (RI) to alert you.

According to the protocol of the 485 bus, its transmission distance can reach 1200 meters, and if you add the amplifier, it can reach 9600 meters, but the farther the distance, the lower the transmission rate. Therefore, optical fibers are recommended for long-distance transmission. The RS-485 interface is the preferred serial interface due to its good noise immunity, long transmission distance and multi-station capability.

According to the protocol of the 485 bus, its transmission distance can reach 1200 meters, and if you add the amplifier, it can reach 9600 meters, but the farther the distance, the lower the transmission rate. Therefore, optical fibers are recommended for long-distance transmission.

The RS-485 interface is the preferred serial interface due to its good noise immunity, long transmission distance and multi-station capability. Because the half-duplex network composed of RS485 interfaces generally only needs two wires, the RS485 interfaces are transmitted using shielded twisted pair cables. The RS485 interface connector uses the 9-pin plug socket of DB-9, the RS485 interface with the smart terminal uses DB-9 (hole), and the keyboard interface RS485 connected to the keyboard uses DB-9 (pin).

The maximum data transmission rate of RS-485 is 10Mbps, and the maximum communication distance of RS-485 is about 1219M

Around 1000 meters is the norm, and it also depends on the complexity of the on-site interference. The higher the rate, the shorter the distance. If the system is not higher than 9600 speed, there is a very good compatible system to replace RS485, and it is a two-wire system.

The communication rate of RS485 is related to the selection of 485 chips, the communication rate of 485 is inversely proportional to the communication distance, the rate is very low in long-distance transmission, and it is not suitable for long-distance communication, and long-distance communication has a more suitable and stable PowerBus bus.

RS-485 has a maximum data transfer rate of 10Mbps

The maximum communication distance of the RS-485 is about 1219m

The transmission distance of 485 can reach 1200 meters.

According to the 485 bus structure theory, the transmission distance of the 485 bus can reach 1200 meters. The condition is that the communication cable is of high quality, the baud rate is 9600, and only one 485 device can be loaded to make the communication distance reach 1200 meters, so usually the actual stable communication distance of the 485 bus often does not reach 1200 meters.

If there are many loads of 485 devices, the impedance of the wire does not meet the standard, the lightning protection of the equipment is complex and the baud rate is increased, and other factors will reduce the communication distance. The 485 bus can communicate with 128 devices. In fact, not all 485 converters can carry 128 devices, according to the model of the chip in the 485 converter and the model of the 485 equipment chip, only according to the lower index of the chip to determine its load capacity.

The significance of communication is as follows:

1. The significance of communication technology to society.

Science and technology play a decisive role in the development of all aspects of society to a certain extent, but technology is not the only factor that can affect social life, it only constitutes an important part of the social development system and is closely related to people's production and life. As far as communication technology is concerned, it has a great influence on the quality of life of society, economic development, political and cultural level, and social relations.

2. The significance of communication technology to economic development.

The core of communication industry research is technology, and only high-end technology can bring them higher benefits and profits. The successful development and implementation of each new technology will not only enable operators to improve their service quality. At the same time, the communication technology of the bureau has driven the development of e-commerce, provided convenience for enterprise market transactions, and created a broader space.

3. The significance of communication technology to the development of social life.

The development of information technology has brought mankind into the digital age and the virtual age, and the way of life in the past has undergone earth-shaking changes, and now the use of computers and networks can become a reality. Communication technology has changed people's lifestyles and shifted more of the center of their lives to the family.

Theoretically, the maximum transmission distance of RS485 can reach 1200 meters, but in practical applications, the transmission distance is shorter than 1200 meters, and the specific transmission distance depends on the surrounding environment. In the transmission process, the signal can be amplified by increasing the relay method, and up to eight relays can be added, which means that the maximum transmission distance of RS485 can reach the axiom in theory. If you really need long-distance transmission, you can use optical fiber as the propagation medium, add a photoelectric converter at both ends of the transceiver and receiver, and the transmission distance of multi-mode optical fiber is 5 10 kilometers, and the transmission distance of single-mode optical fiber can reach 50 kilometers.

How fast? As far as the electrical signal is concerned, it is the speed of electricity, but the communication is based on the data frame, that is, the speed of transmitting a byte depends on the baud rate, the baud rate is fast, but the farther the distance, the lower the baud rate, in order to ensure reliable transmission. This is a pair of contradictions.

I'll give you a comparison chart of the communication distance. The actual communication distance can be increased by adding a repeater.

The RS485 has a maximum wireless transmission distance of 1200 meters. Practice has proved that the use of impedance matching, low attenuation of special cables can reach 1800 meters! More than 1200 meters, repeaters (up to 8) can be added, so that the transmission distance is close to 10km.

Smart meters are developed with the maturity of single-chip microcomputer technology in the early 80s, and now the world instrument market is basically monopolized by smart meters. The reason is the need for enterprise informatization, and one of the necessary conditions for enterprises to have a network communication interface when selecting an instrument. At first, it was a simple process quantity of data analog signal output, and later the instrument interface was RS232 interface, which can realize point-to-point communication, but this way can not realize the networking function.

The subsequent RS485 solved this problem.

I'll give you a comparison chart of the communication distance. The actual communication distance can be increased by adding a repeater.