In the 15-pin connector, the red, green, and blue signals (pins 1, 2, and 3) cannot be shielded from each other, so crosstalk may occur in the 15-pin interconnect. Some high-end monitors and video cards have five independent BNC connectors for RGBHV signals, and five 75-ohm coaxial cables can be used to achieve the highest quality connection. However, ghosting with long cables may be caused by incorrectly terminated devices or passive cable splitters rather than the cables themselves. Ghosting occurs when the impedance does not match, and the ohm (Ω) in the 75 specification causes the signal to be reflected. High-quality cables should not be affected by signal crosstalk so that signals in one wire can induce an unwanted current in adjacent wires or ghosting. Shorter VGA cables are unlikely to cause significant signal attenuation.
There is no standard that defines the quality required for each resolution, but high-quality cables usually conclude coaxial wiring and insulation, making them thicker. The same VGA cable can be used for various supported VGA resolutions, ranging from 320 × 400px Hz, or 320 × 480px Hz (signal bandwidth is 12.6 MHz) to 1280 × 1024px (SXGA) Hz (160 MHz) and up to 2048 × 1536px (QXGA) Hz (388 MHz). In addition, depending on the hardware and software, monitor detection is sometimes unreliable when hot-plugging a VGA connection. However, there is nothing in the design to ensure that the ground pin forms the first contact or the last contact in the connection, so hot swapping may introduce a surge in the signal line, which may or may not be fully protected It is protected from damage. The design of the VGA interface is not hot-swappable (that is, users cannot connect or disconnect output devices while the host is running), although it can be done in practice, and usually does not cause hardware damage or other problems. Devices that meet the standards of the DDC host system can provide a voltage of 5 V ± 5% and provide a current of at least 50 mA to a maximum of 1 A. The four pins possessed Monitor ID bits, which were rarely used VESA DDC redefines some of these pins and replaced the key pins with a +5 V DC power supply. In PS/2, the pin 9 was locked by inserting a female connector hole this prevented a non-VGA 15-pin cable from being inserted into the VGA socket. When the system unit is turned on, it turns on a specific monitor.
The IBM PS/55 Display Adapter defined pin 9 as "+ 12V". When the cable is disconnected (the pin is not connected to the ground), the screen shows a white screen. The IBM 8513 monitor defined pin 5 as "Self Test". The original IBM PS/2 defined different signal assignments. VGA connectors and cables carry analog component RGBHV (red, green, blue, horizontal sync, vertical sync) video signals and VESA Display Data Channel (VESA DDC) data. On laptop computers or other small devices, sometimes a mini-VGA port was used instead of a full-size VGA connector. Many video cards, computer monitors, laptop computers, projectors, and high-definition televisions provided 15-pin VGA connectors.
What is VGA connector? The Video Graphics Array (VGA) connector is a three-row 15-pin DE-15 connector. Tip: You may be interested in this post: What Is USB to HDMI Adapter (Definition and Work Principle).
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