ACR (Advanced Communications Riser) pinout

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Such a slot was designed by ACR Special Interest Group in 2000 as a successor to AMR slot. ACR was designed to have backward-compartibility with AMR (not as incompartible Intel's CNR slot - another successor of AMR).

Correct designation is Advanced Communications Riser (also Advanced Communication Riser, note no ending s in a second word). Sometimes incorrectly referenced as Advanced Card Riser or Audio/Communications Riser.

This slot uses a slightly repositioned and reversed 5V PCI slot; initially it was designed to replace the last one ISA slot that remained on motherboards at a time. But while ISA slot was able to share place with nearest PCI slot (e.g. you may install either PCI card or ISA card using one placeholder of the chassis, as component side of ISA and PCI cards are different), ACR was not able (then, of course, ACR may share its place with ISA slot, but designs that implement it are unknown).

Generally these slots used card orientation as with AMR/PCI (NVIDIA nForce 420-D Reference Board, QDI KD7 (K7V 8366), Biostar M7VIB, Chaintech CT-7VJD2, 7NJS, CT-6VJD, Shuttle AV32, Transcend TS-APR3) to make use of AMR cards possible. Then B is the component (main) side of board, A is the solder side.

ASUS have been seen making this slot with CNR/ISA card orientation (ASUS A7N266, A7V266, CUV266); it allows this slot to share place with nearest PCI slot, but makes AMR and other ACR cards incompartible with it; ASUS produced its own ACR-like cards (ACR-A6CH). ASUS board's component side is A, and solder side is B.

VIA VT5431E Reference Board 2 appears to have slot positioned as AMR/PCI, but it appears slightly shifted to nearest PCI slot. It is unknown accurately, is this really true or not.

SiS 635 Reference Board (one of the earliest boards with ACR support) appears to have this slot shift much more to card bracket than required; it looks like a developer's mistake.

Generally has the same color as PCI (older slots) or specific blue (more recent ones), may be brown as AMR.

Pinout is as follows:

Light green (Rows 1-23 with keyway) = Current AMR Connections
Blue  (Row 24) = EEPROM Connections
Cyan (Rows 25-35, 45-55) = MII/GPSI Connections, interfaces 1 and 2
Yellow (Rows 36-44) = DSL Connections
Red (Rows 56-60) = Wireless Connections (Future implementations)
 

Pins are counted from card bracket to the deeper edge of board. As in AMR, keyway positions are not designated as pin positions, e.g. numbering is A1...A11, keyway, A12...A60.

Note the picture:

Slot name                                         Card orientation

AMR Slot

+-A1--------A11-+-A12--------A23-+               |________________________

| [::::::::::::] [:::::::::::::] |               |     []   []   []

+-B1--------B11-+-B12--------B23-+               |

Standard ACR Slot

+-A1--------A11-+-A12------------------A60-+     |________________________________

| [::::::::::::] [:::::::::::::::::::::::] |     |   []   []   []   []   []

+-B1--------B11-+-B12------------------B60-+     |

ASUS ACR Slot

+-A1--------A11-+-A12------------------A62-+     |

| [::::::::::::] [:::::::::::::::::::::::] |     |   []   []   []   []   []

+-B1--------B11-+-B12------------------B62-+     |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~PCI 5V Slot

+-A1-------------------A49-+-A52-------A62-+     |________________________________

| [:::::::::::::::::::::::] [::::::::::::] |     |   []   []   []   []   []

+-B1-------------------B49-+-B52-------B62-+     |

PCI 3.3V Slot

+-A1--------A11-+-A14------------------A62-+     |________________________________

| [::::::::::::] [:::::::::::::::::::::::] |     |   []   []   []   []   []

+-B1--------B11-+-B14------------------B62-+     |