Audio/modem riser

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AMR slot (brown, at left), with PCI slot (white, at right) for comparison.

The audio/modem riser, also known as an AMR slot, is an expansion slot found on the motherboards of some Pentium III, Pentium 4, and Athlon personal computers. It was designed by Intel to interface with chipsets and provide analog functionality, such as sound cards and modems, on an expansion card. Physically, it has two rows of 23 pins, making 46 pins total. Three drawbacks of AMR are that it eliminates one PCI slot, it is not plug and play, and it does not allow for hardware accelerated cards (only software-based).

One of the design goals of Intel for AMR was to allow motherboard manufacturers a way to implement analog I/O (audio and modem functionality) on an expansion card for FCC certification. Potential cost-savings could then be realized by reusing the card on multiple motherboards and skipping FCC certification for those motherboards.

Technologically, it has been superseded by the Advanced Communications Riser and Intel's own Communications and Networking Riser. However, nearly all riser technologies, such as ACR, AMR, and CNR, have been generally obsoleted in favor of on-board or embedded components.