260:, a form factor which gradually replaced older Baby AT motherboards. During the late 1990s, a great majority of boards were either Baby AT or ATX. Many motherboard manufacturers favored Baby AT over ATX as many computer cases and power supplies in the industry were still designed for AT boards and not ATX boards. Also, the lack of an eighth slot on ATX motherboards kept it from being used in some servers. Later Baby AT boards supported both AT and ATX power connectors in addition to ATX features such as standby power (allowing for a low voltage power switch, as well as Wake-on-LAN/Wake-on-Modem Ring) and
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were mostly shorter than this, typically 9 to 10 in (229 to 254 mm). The size and flexibility of this kind of motherboard were the key to success of this format. The development of bigger CPU coolers—and the fact that they blocked full-length PCI and ISA cards—spelled the end of Baby AT and was the main impetus for its successor
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Unfortunately, the two power connectors it requires are not easily distinguishable, leading many people to damage their boards when they were improperly connected; when plugged in, the two black wires on each connector must be adjacent to each other, making a row of four consecutive black wires (out of the total 12). Technicians developed
184:" full-height drive bays overhang the front of the motherboard. More precisely, the left bay overhangs the motherboard, while the right bay is subdivided into two half-height bays and additionally extends downward toward the bottom of the chassis, allowing a second full-height fixed disk to be installed below a single half-height drive.)
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systems. These motherboards have similar mounting hole positions and the same eight card slot locations as those with the AT form factor, but are 8.5 in (216 mm) wide and marginally shorter than full-size AT boards, with a maximum length of 13 in (330 mm). However, Baby AT boards
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The power connectors for AT motherboards are two nearly identical 6-pin plugs and sockets. As designed by IBM, the connectors are mechanically keyed so that each can only be inserted in its correct position, but some clone manufacturers cut costs and used unkeyed (interchangeable) connectors.
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form factor was introduced, based on the motherboard found in the IBM PC/XT 286 (5162) and soon after all computer makers abandoned AT for the cheaper and smaller Baby AT form factor, using it for computers that spanned several generations, from those that used
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by use of an ATX Form Card. After the industry shifted to ATX motherboard configurations, it became common to design cases and power supplies to support both Baby AT and ATX motherboards.
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compatible designs, contributing to its popularity. In the 1990s many computers still used AT and its variants. Since 1997, the AT form factor has been largely supplanted by
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132:. The IBM AT became a widely copied design in the booming home computer market of the 1980s. IBM clones made at the time began using
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to help assure proper installation, including "black wires together in the middle" and "red and red and you are dead".
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IBM PC AT System Board. This is the original AT motherboard on which the form factor was based.
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The connector at the board is two Molex 15-48-0106 connectors. This mates with a Molex 90331.
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Size and layout of the IBM AT computer's motherboard, used to design compatible products
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An ATX Form Card, used by later Baby-AT motherboards to allow for USB,
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Keyed AT-style power connectors to prevent improper insertion.
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69:Learn how and when to remove this message
976:Small Form Factor Special Interest Group
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32:This article includes a list of general
542:AT power supply connectors with pinouts
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100:comprises the dimensions and layout (
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38:it lacks sufficient corresponding
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471:from the original on 2015-03-16.
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150:Industry Standard Architecture
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220:connectivity through headers
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1003:Motherboard form factors
514:. PC Partner. 8 Jun 2005
240:and a limited number of
509:"35883101 - 883101.pdf"
53:more precise citations.
489:. PC Mag Digital Group
465:"minuszerodegrees.net"
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590:Computer form factors
537:PC Power Supply Links
483:"Baby AT motherboard"
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204:Baby AT motherboard
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552:2012-10-07 at the
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960:CoreExpress
869:COM Express
666:Workstation
547:PC Magazine
487:PC Magazine
298:Power good
256:introduced
164:motherboard
106:motherboard
102:form factor
51:introducing
992:Categories
952:mobile-ITX
877:ESMexpress
598:Listed by
493:31 October
430:References
242:Pentium II
214:PS/2 mouse
168:drive bays
130:processors
122:compatible
59:April 2009
34:references
903:(102×102)
863:(120×120)
847:(165×115)
826:(140×147)
818:(150×150)
810:(170×170)
802:(203×170)
794:(264×267)
786:(203×244)
778:(229×191)
770:(244×244)
762:(254×228)
741:(367×244)
739:Ultra ATX
733:(305x267)
725:(330×229)
717:(325×267)
709:(356×425)
701:(330×216)
693:(305×330)
685:(305×244)
677:(351×305)
652:(419×330)
644:(356×425)
636:(345×381)
628:(305×330)
620:(411×330)
602:size (mm)
444:"Baby AT"
252:In 1995,
104:) of the
911:(100×72)
909:Pico-ITX
895:(114×95)
887:(114×95)
879:(125×95)
871:(125×95)
861:Nano-ITX
855:(149×71)
836:Embedded
824:Mini-STX
816:Mini ATX
808:Mini-ITX
800:Mini-DTX
792:microBTX
768:microATX
550:Archived
469:Archived
196:Variants
108:for the
962:(58×65)
954:(60×60)
946:(70×70)
938:(82×80)
930:(95×55)
922:(96×90)
919:(-Plus)
917:PC/104
776:FlexATX
731:SSI CEB
699:Baby-AT
662:Desktop
626:SSI EEB
618:SSI MEB
609:Servers
379:Ground
368:Ground
353:Ground
342:Ground
314:Yellow
292:Orange
287:Signal
238:Pentium
226:Baby AT
179:⁄
126:upgrade
47:improve
944:Qseven
928:ESMini
518:31 Oct
449:13 Apr
384:White
373:Black
362:Black
347:Black
336:Black
331:−12 V
320:+12 V
281:Color
216:, and
144:Design
118:IBM XT
114:IBM PC
110:IBM AT
96:, the
36:, but
936:SMARC
512:(PDF)
423:+5 V
412:+5 V
401:+5 V
390:−5 V
325:Blue
309:+5 V
254:Intel
650:SWTX
634:HPTX
520:2020
495:2020
451:2021
420:P9.6
417:Red
409:P9.5
406:Red
398:P9.4
395:Red
387:P9.3
376:P9.2
365:P9.1
350:P8.6
339:P8.5
328:P8.4
317:P8.3
306:P8.2
303:Red
295:P8.1
284:Pin
116:and
901:NUC
893:XTX
885:ETX
853:ESM
784:DTX
760:NLX
723:LPX
715:BTX
707:WTX
683:ATX
642:WTX
600:PCB
262:USB
258:ATX
247:ATX
231:286
138:ATX
994::
675:AT
485:.
467:.
235:P5
218:IR
140:.
134:AT
664:/
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568:v
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181:4
177:1
174:+
172:5
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