There are DVI and VGA cable adapters. 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 an 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 include whether or not interlacing is supported as well as 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.
The same VGA cable can be used with a variety of supported VGA resolutions, ranging from 640×350px @70 Hz (24 MHz of signal bandwidth) to 1280×1024px (SXGA) @85 Hz (160 MHz) and up to 2048×1536px (QXGA) @85 Hz (388 MHz). 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. Shorter VGA cables are less likely to introduce significant signal degradation. A good-quality cable should not suffer from signal crosstalk, whereby signals in one wire induce unwanted currents in adjacent wires, or ghosting. Ghosting occurs when impedance mismatches cause signals to be reflected. However, ghosting with long cables may be caused by equipment with incorrect signal termination or by passive cable splitters rather than the cables themselves. Some high-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 (pins 1, 2, 3) 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.