1, Working voltage of USB to RS232 converter
1. Working voltage of USB interface
As one of the standard external interfaces for computers, the USB interface typically operates at a voltage of 5V. This voltage standard has been widely adopted since the birth of USB interfaces, ensuring compatibility and stability between different devices. Therefore, the USB to RS232 converter also receives a voltage of 5V at the USB end.
2. RS232 interface signal voltage
Unlike USB interface, RS232 interface adopts unbalanced transmission method, and its signal voltage range is relatively large. According to the RS232 standard, logic "0" is typically defined as a voltage between+3V and+15V (although in practical applications,+5V to+12V is more common), while logic "1" is defined as a voltage between -3V and -15V. This larger voltage range helps maintain sufficient signal strength and anti-interference ability for RS232 signals when transmitted over longer distances.
However, it is worth noting that the USB to RS232 converter does not directly output the RS232 standard signal voltage when converting USB signals to RS232 signals. On the contrary, the converter internally processes and converts the signal through electronic circuits, ultimately outputting a signal voltage that meets the requirements of the RS232 interface. This conversion process involves multiple steps such as signal amplification and level conversion, ensuring accurate signal transmission and stable equipment operation.
2, Electrical characteristics of USB to RS232 converter
In addition to operating voltage and signal voltage, USB to RS232 converters also have a series of electrical characteristics that are crucial for ensuring normal communication between devices. Here are some key electrical characteristics:
1. Baud rate
Baud rate is a unit of measurement for data transmission rate, representing the number of symbols transmitted per second. USB to RS232 converters typically support multiple baud rate settings to meet the communication needs between different devices. The common baud rate range includes 300bps to 115200bps, etc.
2. Transmission distance
Due to the large voltage range and strong anti-interference ability of RS232 signals, their transmission distance is relatively long. However, when using a USB to RS232 converter, the actual transmission distance may be affected due to the transmission distance limitation of the USB interface (usually ranging from a few meters to tens of meters) and factors such as signal attenuation in the internal circuit of the converter. Generally speaking, the transmission distance of the RS232 end of a USB to RS232 converter does not exceed 15 meters, while the USB end does not exceed 5 meters.
3. Interface protection
In order to protect the interface from interference and damage caused by external factors such as static electricity, USB to RS232 converters usually have interface protection functions. For example, some converters provide electrostatic protection capabilities for contact discharge of 8KV and air discharge of 15KV to ensure stable operation of the equipment in harsh environments.
