Understanding How a USB to Serial Converter Works: A Comprehensive Guide
When discussing USB to serial converters, it's important to understand that these devices play a crucial role in connecting various hardware components to a computer. A typical USB to serial adapter comprises a USB processor chip that processes USB signals and sends them to a serial driver chip, which adjusts the voltages and sends the processed data signals to the serial output. Here, we delve into the inner workings of such converters.
What is a USB to Serial Converter?
USB to serial converters are used for converting digital data from a USB interface into serial communication format, enabling older devices like modems or serial ports to communicate with modern USB interfaces. This conversion is necessary because while USB is a serial interface, older standards like RS232 (now outdated) or RS422 (less old) were widely used for serial communication.
How It Operates
The USB processor chip processes the USB signals, which are already serial in nature. The processed signals are then sent to a serial driver chip that adjusts the voltages and sends the signal to the serial output. This process involves handling voltage differences and handshaking requirements, which are managed by a built-in chip in the cable assembly. A small software driver module then links the USB data into the computer's operating system.
Protocol Handling
The converter handles the protocols on both sides of the connection, including different signal forms, voltages, and speeds. It takes individual packets (characters for RS232) and converts them into USB packets and performs the reverse task in the opposite direction. The protocols used over the USB connection identify the type of converter or adapter involved and select the appropriate USB driver to process the data stream correctly for the type of interface on the remote side of the converter.
USB vs. Serial Communication
Both USB and serial communication operate on the same principle: a single conductor transmitting a single bit of data in one direction. USB is a standardized form of serial interface, often called the Universal Serial Bus. It works like the history's fastest telegraph operator, where data sends in one direction and pauses momentarily to allow the opposite direction to send its data.
In contrast, older parallel connections were bidirectional but could experience issues due to electromagnetism. When multiple conductors carry bidirectional signals, they generate a strong electromagnetic field that can interfere with the other signals. This leads to issues like bit flipping, where a strong enough electromagnetic field can influence another data signal, causing errors in data transmission.
Conclusion
In summary, a USB to serial converter simplifies the process of connecting older serial devices to modern USB ports. It handles the necessary protocol and voltage manipulation to ensure data is transmitted correctly. Understanding the inner workings of these converters is key to utilizing them effectively in various applications.