USB data cable interface

COM interface
COM interface is also called serial port. Most motherboards in the past provided two COM interfaces, COM1 and COM2.
The COM interface is used to connect devices such as serial mouse and external Modem.
The 1/O address of the COM1 interface is 03F8h-03FFh and the interrupt number is IRQ4.
The 1O address of the COM2 interface is O2F8h-O2Fh, and the interrupt number is IRQ3.
Therefore, the COM2 interface has priority over the COM1 interface response. Later, the mouse and other serial port devices adopted PS2 interface and the current popular USB interface, and external devices based on serial port have become rare [6].
USB interface
The full name of USB is Universal Serial Bus. USB was jointly proposed by Intel, Compaq, IBM, Microsoft and other companies in late 1994. USB supports hot plug press, its plug and play advantages, make it become the most important interface mode of computer.
The USB interface has 4 pins, which are USB power (generally 5V), USB data cable +, USB data cable and ground cable.
USB has two specifications, USBI.1 and USB2.0.
The transfer rate of USBI.1 is 12Mbit/s in high-speed mode, 1.5Mbit/s in low-speed mode, 1 Mbit/s= 8 Mbit/s, and 12Mbit/s = l.5 MB/s.
The USB2.0 specification evolved from the USBI.1 specification. It has a transfer rate of 480Mbit/s, or 60MB/s when converted to MB, which is good enough for most peripherals. Enhancement of USB host controller interface (EHCI) defines a compatible with USB1.1 architecture, it can use the USB drive USB 駆 dynamic program. 1 device. This means that all USB 1.1-enabled devices can be used directly on the USB2.0 interface without worrying about compatibility, and accessories such as USB cables and plugs can be used directly.
The USB2.0 standard further increases the interface rate to 480Mbit/s, greatly shortening the transmission time of video and audio files in LCD color TV.
Type-C Indicates the interface
Type-c is an interface Type that can be applied to both PCS (master devices) and external devices (slave devices, such as mobile phones), which is epoch-making.
Micro-USB port
Micro-USB is a USB2.0 standard interface, which is the next version of Mini-USB.
Its characteristics are as follows [8] :
Micro-USB connectors are smaller than standard USB and Mini-USB connectors, saving space [8];
With up to 10000 times of plugging life and strength;
Blind insertion structure design;
Compatible with USB1.1(low speed :1.5Mbit/s, full speed :12Mbit/s) and USB2.0(high speed :180 Mbit/s);
It also provides data transmission and charging.