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How can you easily distinguish the internal connectors on the motherboard?

Cleverly choose internal and external motherboard connectors

In our previous articles, we discussed the computing, memory, and various transmission interfaces of industrial computers. This article will talk about the internal and external connectors of motherboards. Although industrial computers may have different designs according to various applications, and some components may use unique materials or structural shapes to improve stability, the pins and slots of the motherboard components' connectors are based on standard specifications.


To supply power to the components on the motherboard, you must first connect the power supply and enclosure cables to the connectors and headers (exposed pins) on the motherboard. Before this step, please check the diagram in the manual and the text printed on the motherboard to connect the cables with the connectors correctly. Aside from the 24-pin power supply connector, standard connectors found on industrial computer motherboards also include PCIe, SATA Express/SATA 3, and M.2. For industrial computers with high image resolution requirements, such as digital signage, the motherboard must have an independent power supply connector for the graphics card to satisfy the high power requirements of graphics cards.


In addition to the connectors mentioned above, there are more types of connectors for industrial computer motherboards. The power connector on the front panel is a single set of individual pins. It can supply power to the power button, reset button, hard drive LED, power LED, internal speakers, and case. The front panel also contains the audio connectors, which supply power to the headphones and speakers' ports. The fan and water pump connectors provide power for the CPU liquid cooling system. Furthermore, there are USB 2.0, 3.0, 3.1, and S/PDIF (digital audio) connectors.


As for the external ports, the motherboard is considered the device connection hub. It can manage different devices through the I/O controller. The motherboard port can connect the integrated display chip of the CPU with the screen to solve image display problems, which is especially suitable for systems without independent graphics cards. Besides image processing, this design is ideal for peripherals like keyboards and mice, audio devices, and ethernet cables. Furthermore, different versions of ports on the motherboard (such as USB 3.1 Gen 2) can improve speed.


Generally speaking, the external ports of the motherboard are configured on the rear panel, with a removable or integrated "I/O shield" covering the ports. The shield is often made of metal and in contact with the case; therefore, it is grounded. Is the rear panel directly connected to the motherboard or packaged separately? It depends on the setting requirements and structural design. If separate packaging is used, it must be installed during system assembly.


The standard external connection ports for industrial computers are as follows.

USB port:

A standard port used for keyboards, mice, headphones, smartphones, cameras, and other peripherals. USB can provide power and data transmission simultaneously (the maximum transfer speed of USB 3.2 is 20 GBit/s). Current motherboards can be equipped with classic USB Type-A connectors and a slimmer and reversible Type-C connector.


Thunderbolt™ 3 port:

This is a high-speed port for USB-C connectors. The maximum transfer speed of Thunderbolt™ 3 is 40 GB/s, and it supports DisplayPort 1.2 and USB 3.1. The DisplayPort support allows connecting multiple compatible screens through a "daisy chain," controlled by the same computer.


PS/2 port:

A traditional, color-coded 6-pin connector is used for keyboards or mice.


HDMI (High Definition Multimedia Interface):

HDMI 2.1 is a standard digital connection method can support up to 8K resolution (30Hz).



DisplayPort 1.4 is a standard that can support up to 8K resolution (60Hz). Although DisplayPort support is more common in graphics cards than in motherboards, many motherboards can support DisplayPort through the Thunderbolt™ 3 port.


DVI (Digital Video Interface):

This digital 29-pin connector was introduced in 1999. It is a traditional connection port and can be a single-channel or dual-channel DVI with higher bandwidth. Dual-channel DVI can support up to 2560 × 1600 resolution (60Hz). DVI signals can be easily converted to VGA through an adapter.


VGA (Video Graphics Array):

VGA connectors are still found on some motherboards. It is an analog 15-pin connector that can support a refresh rate of 85Hz and a resolution up to 2048 × 1536. The signal quality tends to degrade when the resolution is too high, or the cable is too short.


A graphics card installed on the motherboard's expansion slots will provide display port options, such as HDMI, DisplayPort, DVI, and VGA, for the user to choose from when connecting to the built-in graphics device of the motherboard.


Another critical aspect of external AV connectors is audio. Most computer cases will be equipped with two analog 3.5 mm audio ports on the front panel. They typically are labeled as headphones (headphone output) and microphone (microphone input). The motherboard's back panel is often equipped with 6 color-coded and labeled 3.5 mm analog audio ports for connecting multi-channel speaker systems.


Overall, the most significant difference between industrial computers and general consumer/commercial computers is the internal and external connectors of the motherboards. General consumer/commercial computers have fixed usage settings. Therefore there is not much variety in function requirements. On the other hand, industrial computers are used in diverse applications. Each setting will have special requirements due to different operational needs; for example, POS systems for the retail industry would need multiple screens and should be compatible with mobile inventory devices. The functional requirements of factory production lines are more straightforward but are often more demanding in terms of robustness and reliability. Therefore, the connectors and ports should not easily detach, and the connection must be reinforced. For information on choosing the correct connectors for specific settings, companies can contact DFI Inc. Our team will provide professional services to help customers build an industrial system that complies with your performance requirements and specifications.