An ATX style motherboard has the parallel, serial ports, keyboard and mouse connectors soldered to the board. An AT board will have pin connectors for the parallel, mouse etc. You must supply the actual connectors for these boards. The power supply for an AT has 2 seperate plugs, they do look similar to the single plug of an ATX but they do not interchange. There are worlds of differences in the two boards. Stick with an ATX motherboard, its getting hard to find cases and power supplies for AT style boards.
P4 email@example.com dual R134A phase change chillers with 600watt thermoelectric array. Capable of -70F
Nixie tube numeric display control panel and pneumatic motherboard tray.