Hi,
AT = older = power supply power was applied by turning a mechanically
switch wired on, that was connected to case. They usually had 2
connections to the main board (p8/p9) = usually pre Pentium II class machines
ie Pentium, 486, 386, 286, 8086. Needs a manual operation to turn on.
That is, the switch is in either the on or off position. Power is not
applied to the board until the switch is on. Some packard bells for
instance used a rod from the case to the power supply, and that rod turned
the switch on that was located inside the power supply.
ATX = Newer= Power supply power is connected electroincally thru a relay in
the main board. Usually PII class and newer. Usually a single rectangular
block is connected to the board from the power supply (for p4 may be 1 or 2
more connections necessary depending on rambus or DDR or pc133 memory).
The switch from the case connects to the main board and by momentary short
turns the power on or off thru a relay on the board. This design allows
for new features like wake on lan, wake on ring, powering the system up by
hitting a key, etc.
There is always some power going to the board (unless the power supply
rocker switch, if equipped, is turned off). That is why the new boards
have a LED to let you know that power is applied.
There were some in between setups by Dell, Gateway, ect. They used to have
the P8/p9 connector and they had a 3rd similar connector that went to their
propriorary boards and the boards were turned on by a relay switch
connected from the board to the case. You could call these the Early ATX
Systems, the ones that were out before the ATX standard took over.
At 09:44 AM 01/08/2003 +0200, you wrote:
>what are AT and ATX computers?
>Best regards,
>Huynh Minh Huong
>E-mail: [log in to unmask]
God Bless America!
Joe Lore
MicroComputerCenter, Inc.
781-933-5530 / [log in to unmask]
Visit our website regularly for FAQs,
articles, how-to's, tech tips and much more
http://freepctech.com
|
