Editing Advanced Communications Riser

{{Short description|PC motherboard expansion slot format}}
{{One source|date=September 2023}}

[[File:ACP-Bus @ ASUS A7V266.jpg|thumb|ACR expansion slot (right), on the left 2 PCI slots]]

The '''Advanced Communications Riser''', or '''ACR''', is a [[Computer form factor|form factor]] and technical specification for [[PC motherboard]] [[expansion slot]]s.<ref name=":0">{{Cite web |date=2000-07-19 |title=Initiative readies advanced communications riser card standard |url=https://www.edn.com/initiative-readies-advanced-communications-riser-card-standard/ |access-date=2023-09-04 |website=edn.com}}</ref> It is meant as a supplement to [[Peripheral Component Interconnect|PCI]] slots, a replacement for the original [[Audio/modem riser]] (AMR) slots, and a competitor and alternative to Intel's [[communications and networking riser]] (CNR) slots.

==Technology==
The ACR specification provides a lower cost method to connect certain [[expansion card]]s to a [[computer]], with an emphasis on audio and communications devices. [[Sound card]]s and [[modem]]s are the most common devices to use the specification.  ACR and other [[riser card]]s lower hardware costs by offloading much of the computing tasks of the [[peripheral]] to the [[Central processing unit|CPU]].

ACR uses a 120 pin PCI connector which is reversed and offset, retaining [[backward compatibility]] with 46 pin AMR cards while including support for newer technologies. It is also more cost-effective and simple for the manufacturer, since the connectors are identical to the PCI connectors already purchased in quantity. New features supported by ACR include standards for an [[EEPROM]] for storing model and vendor information, [[Universal Serial Bus|USB]] support, and the ''Integrated Packet Bus'' for [[digital subscriber line]] (DSL), [[cable modem]], and [[wireless network]]ing support.

==History==
The ACR specification was created by the ''Advanced Communications Riser Special Interest Group'' (ACR SIG) in 2000 with the intent to replace the AMR specification.<ref name=":0" /> Because it was backwards compatible with AMR cards, and technically superior, it quickly replaced it.

ACR is rendered obsolete by discrete components mounted on the motherboard.

==See also==
*[[Mobile Daughter Card]] (MDC), a version of ACR for mobile devices
*[[GeoPort]], a similar standard for the [[Apple Macintosh]]

== References ==
{{Reflist}}

[[Category:Motherboard expansion slot]]
[[Category:Sound cards]]