Hopefully this should clear things up
http://www.hardwareanalysis.com/content/image/10185/
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ACR
Abbreviation for "Advanced Communication Riser"? Possibly competition for Intels Communication network Riser Slot (CNR), which provides with auxiliary plug-in cards for sound, net and InterNet connection. The chip sentence manufacturers VIA, 3Com and other one developed this alternative
Although VIA itself during the naming nothing original let break in, offers the ACR Slot and/or the supplementary tickets nevertheless a piece of news: a DSL modem. Otherwise the Slot offers the used features: Place for sound -, net or analog modem maps. Also its Design is well-known: around 180 degrees of turned PCI Slot, with which however not all 120 pins are occupied. So the standard can be also extended. And downward-compatibly to AMR is ACR also. Thus ACR has the nose compared with CNR in front, because takes up no AMR maps
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AMR/CNR/ACR
Contrary to Onboard elements contain many chip-corrode AC'97(Audio) - or Ethernet functions, which require however additional construction units and Treiber(Software).
Over to the different market conditions to react to be able by the chip sentence manufacturers special Slots for Motherboards was created, which could be extended with appropriate extension cards economically. Due to the small construction unit quantity on the plug-in cards are cheaper this to manufacture than adequate PCI maps. The efficiency is less high according to.
The additional extension of a computer system with a AMR -, Cnr or ACR plug-in card is practically not possible. The non-uniform driver model for the different Motherboards and plug-in cards makes this solution interesting only for PC manufacturers, that manufacture complete systems in large numbers of items.
In the retail trade AMR is not available -, Cnr and ACR plug-in cards.
AMR(Audio modem Riser) & CNR(Communication network Riser)
AMR was brought 1998 by Intel into being, in order to realize the modem and sound functions of AC'97 and a USB channel.
In the year 2000 Intel an LAN interface supplemented and the SMBus. And at the same time the whole in CNR renamed.
ACR(Advanced Communication Riser)
The specification of ACR was published by a consortium of firms, to which also AMD belong and VIA.
The ACR Slot has easy similarity with the PCI Slot. The bar between the pin rows is however on the other side of the Slots. AMR plug-in cards fit also in this Slot.
ACR contains an LAN interface, conclusion possibilities for DSL modems and wireless Netzwerke(nur the USA).
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AMR (Audio/Modem Riser) is a specification developed by Intel for packaging the analog I/O audio functions of modem circuitry together with a codec chip (which converts back and forth from analog to digital) on a small board that plugs directly into a computer's motherboard. The small board is called a riser because it rises above the motherboard rather than laying flatly on it. Having this circuitry on a riser means that it doesn't have to be part of the motherboard itself. Because getting certification for the manufacture of a new motherboard design is a lengthy process, removing this function from the motherboard provides more flexibility for manufacturers and allows advances in audio modem design to be implemented more easily. Another specification, MDC (Mobile Daughter Card) is the equivalent of AMR but for use in mobile computers.
In the past, an internal modem was installed in one of several slots inside the computer chassis and an external modem was plugged into a serial port at the rear of the computer. With AMR design, the slot can now be used for other purposes. The AMR card can also provide the foundation for higher-quality audio solutions such as 3D positional audio and better MIDI music production.
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AMR
Abbreviation for "audio modem Riser" ("rise "- English: Upward gradient, hill, stairway, rise)? Intel pursues the idea to the turn of the century with AC97 the fact that modern processors have sufficient power reserves (became), in order to compute apart from the normal tasks also still those few analog data. Audio and modem data are concretely meant, and the AC97-Spezifikation (audio codec 97) and the AMR Slot came out.
The normal: On the Main board are the AC97-Controller, the primary AC97-Codec and the associated audio patch cords. On the optional modem Riser map in the AMR Slot the secondary modem codec as well as the telephone plugs sit. The cheap: Only the AC97-Controller and the AMR Slot are on the Main board, which offers then no sound abilities. With the Riser map one can select now between a pure sound codec map and one with sound and modem codecs. Whether this combination map with an efficient primary mixing codec is developed or whether it combines a primary audio codec and a secondary modem codec, hardly plays a role. The integrated: On the Main board are all necessary codecs. Again it is no matter whether a complex codec of everything can divide or two codecs audio and modem transformations. The board must connections for audio and telephone offer, can however without a AMR Slot do<P ID="edit"><FONT SIZE=-1><EM>Edited by Clarentavious on 01/11/03 09:55 AM.</EM></FONT></P>