Card Slot Identification

Identifying the card slots on a motherboard

There are many different card slot types that you will run in to here at Free Geek, so it can be rather challenging to determine which type you are looking at. An I/O (Input/Output) bus slot allows the user to add components to the computer, increasing the systems capability of performing to the users needs or wants. Below are some guidelines to help determine the slot type on the motherboard and the slot on the card itself.

But before we can discuss these we must talk about the basic motherboard layout. To arrange the board so that you can easily find the card slots, you should take an example board and turn it so that the on-board cluster or AT keyboard connector is facing you. Now you can see the card slots to the right of the on-board connectors.

The most reliable ways to identify them are:

   1.  Checking the distance between the outside of the box on the motherboard and the beginning of the pins
 
      AGP slot will have more than a 2" gap between plate and pins
      PCI slot has a slightly more than a 1" gap between plate and pins
      PCI-express video slot will have approximately 1 1/4" between plate and pins
      ISA slot will have a little more than a 1/2" gap between the plate and pins

   2.  Looking at the connector contact openings on the slots themselves

      AGP slot has connector openings that are very fine and close together
      PCI slot has connectors that are much bigger than either the AGP or PCI-e slots 
      PCI-e slot has connectors that are very small and fine, similar to the AGP
      and the ISA slot (oldest of the commonly seen slot types) has very large connectors in which the metal contacts can easily be seen

There are standard colors for the card slots: black for I.S.A., tan for P.C.I. brown for A.G.P. but that does not mean that all motherboard vendors will stick with those colors. So, you cannot rely on the colors of the slot plastic to be able to identify them.

The ISA slot

The Industry Standard Architecture slot was first implemented in the early 1980's by IBM. This card was capable have transferring data to and from the computer. Opening up a world of possibilities from printing to networking with other computers. The 8 bit technology of the ISA card was soon improved upon and a 16 bit bus was implemented. Increasing the slot and card length allowed for data to transfer In and Out of the computer much faster. The bright side of the new architecture was that you could still use a 8 bit card in a 16 bit slot, allowing users who could only afford a new computer and not new cards to maintain the usability of there new computer.While the 8 bit ISA slot and 16 bit ISA slot differ in length they both start 1 in. from the back of the motherboard.