VESA Local Bus (VL-Bus) VL-bus is a bus architecture developed by VESA
(Video Electronics Standards Association) for use with the 486 processor and
video cards. A local bus is one that is attached to the same bus structure used
by the CPU. VL-bus is a 32-bit bus that supported bus mastering. The PCI bus
has essentially replaced the VL-bus on modern PCs. If your PC has a VL-bus
expansion slot, it is the one next to the ISA and EISA slots that has the extra slot
added to the end and is about four inches long in total.AGP is fast replacing PCI as the interface of choice for video cards because of its faster
transfer rates. In fact, AGP has evolved into several standard versions, each noting its
multiple of the original standard. For example, AGP 1X has a data transfer rate of
266MBps (compared to PCI’s 133MBps), AGP 2X supports 533MBps, and AGP 4X trans-
fers data at 1.07GBps.Video Connectors
Regardless of the type of internal interface a video card uses, virtually all video ports use
a female 15-pin DB port and connector. This port is shown in Figure 19-16.(^502) PC Hardware: A Beginner’s Guide
Figure 19-16. The standard DB-15 VGA video port
Video port