Personal Computer Expansion Buses

This is a subdivision of the main Interface Bus Tree for PC buses. This page provides descriptions for common PC expansion buses.

ACR Bus: Advanced Communication Riser interface. An OEM Riser specification. This latest version provides for modem support, LAN and xDSL support, and Audio support. ACR was preceded by CNR and AMR, both listed on this page. The ACR standard is backwards compatible with AMR.

ADB Bus: The Apple Desktop Bus was a serial bus used by Apple computer to drive the mouse and keyboard. The ADB bus is OBSOLETE and was replaced by the Firewire interface bus.

AGP Bus: The Accelerated Graphics Port is used as a Video Local bus on the Personal Computer. The PCI-Express card bus has replaced the AGP bus on personal computers.

AIMM Bus: AGP Inline Memory Module defines a memory card that plugs into the AGP slot, on motherboards with an integrated graphics core [that don't require a Video card]. The AIMM card provides an additional 4MB of dedicated video memory. This interface solution is OBSOLETE.

AMR Bus: Audio/Modem Riser specification defines a hardware scalable OEM PC mother board riser board and interface, which supports both audio and modem functions. An MR slot will provide a Modem function, while an AMR slot will provide both an Audio and Modem function. The modem is a WinModem.

Apple Computer Buses: Macintosh Computer Buses.

AT Bus: The ISA AT Computer Card, or PC-AT bus was replaced by the PCI bus and is OBSOLETE.

ATX Form Card Connector Pinout: The ATX Form Card was designed to up-grade the old AT form factor mother board to allow for ATX connectors.

ATX Riser Card: Riser card used with ATX form factor mother boards.

CardBay: Places the USB onto the PC Card PCMCIA format, but has been obsoleted by the ExpressCard release.

CardBus: A 32 bit, 33MHz PCMCIA Card. CardBus replaces the 16 bit PC Card version of the PCMCIA standard

CNR Bus: Communication and Networking Riser Specification supports the audio, modem, and local area network (LAN) interfaces of core logic chip sets. This standard does not support an expansion slot.

CompactFlash Card: Mass Storage removable Flash Memory card operates like an ATA drive using Flash memory. Devices are about 1/3 the size of a Type II PC Card.

DataFlash Card: Mass Storage removable Flash Memory card.

Device Bay: A defined form factor peripheral which connects via USB and/or Firewire to the PC, but as of 2001 is not supported by Windows.

EISA: Extended Industry Standard Architecture [EISA] or Enhanced ISA bus: 8MHz @ 8/16/32 bits data bus, 32 bit address bus; PC Expansion Bus, compatible with ISA. The EISA interface is OBSOLETE.

ExpressCard: PCMCIA ExpressCard is the new form factor for PCMCIA Circuit Cards which utilizes either USB and PCI Express buses.

GPA Bus: Graphics Performance Accelerator defines a memory card that plugs into the AGP slot on mother boards with an integrated graphics core that don't require a Video card.

HTX Slot {HT slot for EATX motherboards using HyperTransport Daughter cards}

ISA/XT Bus: IBM Compatible ISA XT bus ran at 4.77MHz using a 8 bit data bus. The ISA XT bus is OBSOLETE, replaced by the expanded ISA AT bus expansion board.

Macintosh Computer Buses: Apple Computer Buses.

MCA: Micro Channel Architecture bus: Designed to correct the problems with the ISA bus, but never caught on out side of IBM machines. The bus is Obsolete and was later replaced by the PCI bus.

Memory Stick Flash

Mini PCI: Is a reduced form factor version of a PCI card. Mini PCI was designed for the NoteBook/ Laptop market, i.e mobile systems.

Mini PCI Express: Is a reduced form factor version of a PCI Express card. Mini PCI Express was designed for the NoteBook/ Laptop market, mobile systems.

Miniature Card: Miniature Card is a reduced size implementation of PCMCIA.

Mother Board Types: All the different Mother Board sizes and types.

Multimedia Card: Multimedia Card is a flash memory card.

NUbus: IEEE Std 1196-1987 is an Apple [Macintosh and NeXT Computer] expansion bus using a 32 bit address and data bus operating at 10MHz. This bus is OBSOLETE being replaced by the PCI bus.

PCI Bus: The Peripheral Component Interface 'PCI' [Parallel] Bus was originally developed as a local bus expansion for the PC.

PCI-X Bus: This Peripheral Component Interface addendum [PCI X] is an enhancement to the current 64 bit 66MHz PCI bus specification used in the server environment.

PCI Express Bus: Serial PCI Bus uses two low-voltage differential LVDS pairs, at 2.5Gb/s in each direction. PCIe is set to replace the AGP slot on PC Mother Boards.

PCMCIA PC Card: Implementation of the 16 bit ISA Bus on a PCMCIA card. The PC Card is OBSOLETE.

PCMCIA Cardbus: Implements the 32 bit PCI bus in a PCMCIA form factor:

PCMCIA Miniature Card: Miniature Card is a smaller form factor implementation of PCMCIA.

PCMCIA ExpressCard: "Newcard" is the new form factor for PCMCIA Circuit Cards and will utilize either USB and PCI Express buses.

PictBridge: provides print services between devices like printers and digital cameras. PictBridge uses USB as the physical layer.

Reduced Size Multimedia Card: Reduced Size Multimedia Card [RS-MMC] is a flash memory card format.

Riser Cards {Personal Computer Expansion Bus Riser Board standards include: ACR [Advanced Communication Riser], AMR [Audio/Modem Riser], and CMR [Communication and Networking Riser].

Riser Board: Card Manufacturers.

S-100: Obsolete Altair bus, from 1975.

Sbus: [IEEE-1496] is a computer expansion card bus used for Sun workstations. Sbus is OBSOLETE, replaced by the PCI bus.

SD Card: Secure Digital Card. A stamp-sized flash memory card which is removable.

SDIO Card: Secure Digital I/O Card. A stamp-sized flash memory card which is removable.

SIOM: Server I/O Module, a new form factor module using PCI Express.

SmartCard Bus: ISO 7816; Defined plastic chip card designed to store data via a magnetic strip

SmartMedia: SmartMedia is another flash memory card format type.

SSFDC Bus: Solid State Floppy Disk Card, is a Removable NAND-type small flash memory card. SSFDC is the old name for SmartMedia}

VLB: VESA [Video Electronic Standards Association] Local bus [VLB or VL-Bus], ran at 33MHz using a 16/32 data bits.
The PC Local Bus Expansion, VLB bus is now obsolete.

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Modified 1/31/12
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