Advanced Communications Riser - AbsoluteAstronomy.com

The Advanced Communications Riser, or ACR, is a form factor and technical specification for PC motherboard expansion slots

Expansion slots

Expansion slots are specific slots on a PC motherboard that facilitate the placement of expansion cards.All such expansion slots are colour coded, and are built in such a way that only a specific type of card or device can interface with/ be inserted into the device.- Types :Common types of...

. It is meant as a supplement to PCI

Peripheral Component Interconnect

Conventional PCI is a computer bus for attaching hardware devices in a computer...

slots, a replacement for Audio/modem riser

Audio/modem riser

The audio/modem riser, also known as an AMR slot, is a riser expansion slot found on the motherboards of some Pentium III, Pentium 4, Duron, and Athlon personal computers...

(AMR) slots, and a competitor and alternative to Communications and Networking Riser

Communications and Networking Riser

Communications and Networking Riser is a slot found on certain PC motherboards and used for specialized networking, audio, and telephony equipment. A motherboard manufacturer can choose to provide audio, networking, or modem functionality in any combination on a CNR card...

(CNR) slots.

Technology

The ACR specification provides a lower cost method to connect certain expansion card

Expansion card

The expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus.One edge of the expansion card holds the contacts that fit exactly into the slot...

s to a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

, with an emphasis on audio and communications devices. Sound card

Sound card

A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...

s and modem

Modem

A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...

s are the most common devices to use the specification. ACR and other riser card

Riser card

A riser card is a printed circuit board that picks up a multitude of signal lines via a single connector on a mainboard and distributes them via dedicated connectors on the card....

s lower hardware costs by offloading much of the computing tasks of the peripheral

Peripheral

A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....

to the CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

.

ACR uses a 120 pin PCI connector which is reversed and offset, retaining backward compatibility

Backward compatibility

In the context of telecommunications and computing, a device or technology is said to be backward or downward compatible if it can work with input generated by an older device...

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

EEPROM

EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g., calibration...

for storing model and vendor information, USB

Universal Serial Bus

USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....

support, and the Integrated Packet Bus for Digital Subscriber Line

Digital Subscriber Line

Digital subscriber line is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop. In telecommunications marketing, the term DSL is widely understood to mean Asymmetric Digital Subscriber Line ,...

(DSL), cable modem

Cable modem

A cable modem is a type of network bridge and modem that provides bi-directional data communication via radio frequency channels on a HFC and RFoG infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable Internet, taking advantage of the high...

, and wireless network

Wireless network

Wireless network refers to any type of computer network that is not connected by cables of any kind. It is a method by which homes, telecommunications networks and enterprise installations avoid the costly process of introducing cables into a building, or as a connection between various equipment...

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. 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.

Technology

History

See also