A smaller version of the original AT motherboard used in the IBM PC/AT. Introduced in 1987, the Baby AT reduced width from 12" to 8.5". Although its maximum length was 13", most boards were only 9" or 10" long. The Baby AT was the first PC motherboard to build in sockets for I/O ports (serial, parallel, etc.), which were cabled to connectors on the back of the case. Widely used in 386, 486 and early Pentium PCs, the Baby AT was superseded by the ATX motherboard. See ATX motherboard and PC motherboards.