What are the types of data lines?



A COM interface is also called a serial port. In the past, most motherboards provided two COM interfaces, COM1 and COM2.

What are the types of data lines?

COM interface

A COM interface is also called a serial port. In the past, most motherboards 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 takes precedence over the COM1 interface response. Later, the mouse and other serial port devices adopted PS2 interface and the current popular USB interface, and the external devices based on serial port have become rare [6].

USB port

The full name of USB is Universal Serial Bus, which means "universal serial bus" in Chinese. USB was introduced in late 1994 by Intel, Compaq, IBM, Microsoft and other companies. USB supports hot plug press, its plug and play advantages, make it the most important interface mode of computer.

The USB interface has 4 pins, which are USB power supply (generally 5V), USB data cable +, USB data cable and ground cable.

USB has two specifications, USBI.1 and USB2.0.

The transmission 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 is an evolution of the USBI.1 specification. It has a transfer rate of 480Mbit/s, or 60MB/s when converted to MB, which is sufficient 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 PC(master device) and external devices (slave device, such as mobile phone), which is epoch-making [7].

Micro-USB port

Micro-USB is a USB2.0 standard interface, is the next version of Mini-USB.

Its characteristics are as follows:

Micro-USB connectors are smaller than standard USB and Mini-USB connectors, saving space;

With up to 10000 times of plug 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.