In what ways is the USB bus better than the RS232C bus?

Question

What will be an ideal response?

Answer 1

It’s hard to know where to begin! The RS232C serial interface used by early PCs (and still in use today in some areas) was designed in the 1960s in a pre?microprocessor, pre?IC era. That is, it is a bus with no built in intelligence. It was designed for slow speed computer to modem links, and has both signal paths and control signals. It uses either a 25?pin or a 9?pin connector that is large and bulky and often transfers data at speeds below 9,600 baud (about 1,000 bytes/s)

Computers of the 1970s and 80s adopted the RS232C bus as a link to peripherals such as printers. Data transmission was slow and the system often had to be manually configured for each computer.

USB is a modern bus operating at a speed of 1.5 Mbit/s to 480 Mbit/s (and faster in the 3.0 version). Connectors are small and include two power lines as well as the data paths. Consequently, some devices can be powered directly from the bus itself (e.g., flash memory, mice, keyboards, and small hard drives). Data and control signals are integrated; that is, there are no control lines on the USB bus. Moreover, with intelligence built into the bus, it is possible for the bus to support multiple users (RS232C was strictly point?to?point). Even better, USB supports plug?and?play whereby devices can transfer drivers directly to the computer invisibly to the user. For example, you plug in a new printer to your computer’s USB port and after a few moments the computer and printer communicate with each other as if they’ve been life?long friends. RS232C interfaces often required you to load a device driver from disk, configure the bus by soldering connections, and then set a series of tiny switches on a circuit board in the computer.