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RS232 Interface Details

RS232 interface is a standard for serial communication jointly developed by the American Electronics Industry Association (EIA) in 1970 in conjunction with Bell Systems, modem manufacturers and computer terminal manufacturers. Its full name is Technical Standard for Serial Binary Data Interchange Interface between Data Terminal Equipment (DTE) and Data Communication Equipment (DCE).

RS232 interface is now most commonly used for LED monochrome display interface, belonging to the serial interface connecting computer and LED display. However, the maximum transmission rate of R232 is generally only 20 kb/s, and the distance is relatively short, generally no more than 20 meters. However, since the data transmitted is mainly text or gif, it can also meet the normal use of LED monochrome screen, which is also one of the processes to reduce the cost of LED display manufacturers.

Generally, when the LED monochrome screen we use sends data, the RS232 signal swings between positive and negative levels, the positive level is between +5V and +15V, and the negative level is between-5V and-15V. When receiving data, the positive level is between +3V and +12V, and the negative level is between-3V and-12V. The transmission distance limitation mentioned above is caused by the difference between the transmission level and the reception level. The interface uses a signal line and a signal return line to form a common ground transmission form, which is also prone to common-mode interference. Of course, this is also because RS232 interface invented earlier, now there are RS485 these similar interfaces exist, can support a longer transmission distance, can be to tens of meters or even a few kilometers, because it uses a balanced transmission and differential reception method, resulting in it has a strong common-mode interference rejection capability, so that its transmission signal is not lost in the transmission of several kilometers.

Of course, due to the RS232 transmission rate and other issues, the general LED monochrome screen is rarely made into a large LED screen, unless the current popular USB interface transmission is used.

Article by: LED display,LED display manufacturers,LED large screen http://www.fsxd.net Power Technetium photoelectric finishing

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