(Advanced Technology EXtended motherboard) The PC motherboard that superseded the Baby AT design. The ATX layout rotated the CPU and memory 90 degrees, allowing full-length expansions to be plugged into all sockets. The power supply blows air over the CPU rather than pulling air through the chassis. Introduced in 1995, the ATX was the first PC motherboard to not only include I/O support (serial, parallel, mouse, etc.), but to place all the connectors directly on the motherboard. Prior to the ATX, only the keyboard connector was attached to the motherboard. Numerous variations of the ATX were subsequently introduced with both smaller and larger form factors, including the microATX, Mini ATX, FlexATX and Extended ATX (see PC motherboards).