A Video Graphics Array connector is a three-row 15-pin DE-15 connector. The 15-pin VGA connector
is found on many video cards, computer monitors, and high definition television sets. On laptop
computers or other small devices, a mini-VGA port is sometimes used in place of the full-sized
VGA connector. DE-15 is also conventionally called RGB connector,
D-sub 15, mini sub D15, mini D15, DB-15, HDB-15, HD-15 or HD15.
VGA connectors and cables carry analog component RGBHV video signals, and VESA Display Data
Channel data. In the original version of DE-15 pinout, one pin was keyed by plugging the
female connector hole; this prevented non-VGA 15 pin cables from being plugged into a VGA
socket. Four pins carried Monitor ID bits which were rarely used; VESA DDC redefined
some of these pins and replaced the key pin with +5 V DC power supply.
The VGA interface is not engineered to be hotpluggable, although in practice this can
be done and usually does not cause damage to the hardware or other problems. However,
nothing in the design ensures that the ground pins make a connection first and break last,
so hotplugging may introduce surges in signal lines which may or may not be adequately protected
against. Also, depending on the hardware and software, detecting a monitor being connected
might not work properly in all cases.
Cable quality
The same VGA cable can be used with a variety of supported VGA resolutions, ranging from
640×350px @70 Hz to 1280×1024px @85 Hz and up to 2048×1536px @85 Hz. There are
no standards defining the quality required for each resolution, but higher-quality cables
typically contain coaxial wiring and insulation which make them thicker. A quality cable should
not suffer from signal crosstalk which occurs when the signals in one wire induce unwanted
currents in adjacent wires, ghosting which occurs when impedance mismatches cause signals
to be reflected, and other signal degradation effects; shorter VGA cables are less likely
to introduce significant degradation.
Some higher-end monitors and video cards featured 5 separate BNC connectors for RGBHV signal,
allowing highest quality connection using five 75 ohm coaxial cables. Within a 15-pin
connector, the red, green, and blue signals cannot be shielded from each other, so crosstalk
is possible within the 15-pin interconnect. BNC prevents crosstalk by maintaining full
coaxial shielding through the circular connectors, but the connectors are very large and bulky.
The requirement to press and turn the plug shell to disconnect requires access space
around each connector to allow grasping of each BNC plug shell. Supplementary signals
such as DDC are typically not supported with BNC.
Adapters There are DVI to VGA adapters and cables.
They do not carry audio channels, thus separate path for audio should be used, if needed.
To connect VGA to interfaces with different signaling and vice versa converters may be
used. Most of them need external power source to operate and are inherently lossy.
VGA to SCART converter that passes through color information is possible, because VGA
— SCART RGB signals are electrically compatible, except for synchronization. Modern graphics
adapters are able to widely modify their signal in software, including refresh rate, sync
length, polarity and number of blank lines. Particular issues are, whether interlacing
is supported and if the resolution can be set to 720×576 in PAL countries. Under these
strict conditions, a simple circuit to combine the VGA separate synchronization signals into
SCART composite sync may suffice. See also
Component video Digital Visual Interface
Display Data Channel Extended display identification data
HDMI List of video connectors
Super Video Graphics Array Video Electronics Standards Association
VGA extender References
External links DE-9 pinout
DE-15 VESA DDC pinout DE-15 to 5 BNC