What is the COM port on the computer motherboard?

What is the COM port on the computer motherboard?

1. Definition

COM port (Communication Port) is a serial communication port, which is an interface for data transmission. It is a physical interface for asynchronous serial communication between computers and external devices (such as modems, mice, industrial equipment, etc.). In the early days of computer development, COM ports played an extremely important role and are still widely used in some specific industrial control, communication and other fields.

2. Working principle

COM port uses serial communication, which means that data is transmitted bit by bit. It uses specific communication protocols such as RS-232 (the most common one), RS-422 or RS-485 to send and receive data. For example, in the RS-232 protocol, data is sent from the computer to the external device through the transmit line (TXD), and the data from the external device is received through the receive line (RXD). The communication process also involves some control signals, such as request to send (RTS), clear to send (CTS), data terminal ready (DTR) and data set ready (DSR), which are used to coordinate the data transmission process and ensure the accuracy and stability of communication.

3. Appearance and interface type

Physical interface: The traditional COM port is a 9-pin (DB9) or 25-pin (DB25) D-type interface. Among them, the 9-pin COM port is more common, and its pin definition has a clear standard. For example, under the RS-232 standard, pin 1 is usually used for data carrier detection (DCD), pin 2 is used for receiving data (RXD), and pin 3 is used for sending data (TXD).

Internal interface (on the motherboard): On the motherboard, the COM port is connected to components such as the processor through the chipset and related circuits. The motherboard manufacturer can choose to integrate the COM port controller on the motherboard and lead it out through the pin header (usually called the COM port pin). The user can use an adapter cable to convert it to a standard external D-type interface, or directly connect some devices with COM interfaces (such as some industrial control modules) to these pins through a flat cable.

Intel Sandy Bridge/Ivy Bridge Thin Mini-ITX with VGA/HDMI/2*LVDS，LPT，2*COM，Single LAN，2*SATA，MSATA，DDR3L， WIFI/4G Module，DC12V Input，which is Angthumb GW7-POS23 V1.2,the following parameters are supported：

▲Support Intel Sandy Bridge/Ivy Bridge series processors

▲Support DDR3L memory, up to 8GB 1600MHz SDRAM

▲Support stereo dual-channel ALC887 chip sound card or USB sound card

▲Support 2 serial ports, 1 parallel port; support 1 RJ45 Gigabit network card interface

▲Support 2 USB3.0, 6 USB2.0

▲Support 2 7Pin SATA interfaces, 1 MSATA interface

▲Support cash box interface

▲Support 1 Mini PCIE expansion slot (including 8pin SIM card slot), support WIFI/4G Module

▲Support 1 rear VGA interface, 1 pin HDMI interface, 2 LVDS interfaces, and support simultaneous dual display

▲Support DC12V power input

▲Support Windows7, Windows10 32/64 bit, Linux operating system

Angxun has been in the motherboard industry for more than 20 years. Registered the brand Angthumb in many countries,we have focused on the production and research and development of intel motherboard,all in one motherboard,and Industrial motherboard,server motherboard ，RAM,SSD,CPU,GPU etc.The website is : www.angthumb.com to know more!