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AMR, CNR, and ACR: How useful were they?

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First post, by dormcat

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I have noticed that most motherboards of Pentium 3 / K7 (Athlon) era have an audio/modem riser (AMR) slot. Some MB have less common communications and networking riser (CNR) or even more rare advanced communications riser (ACR).

I know their existence have something to do with FCC regulations (so MB manufacturers could just send one module for FCC reviewing and use it on all their MB, rather than sending all models of MB to FCC), but I haven't seen any computer using those slots in person. Most -- if not all -- computers of the era with no sound card, modem, or NIC integrated into MB kept using PCI versions of those expansion cards, until a couple years later most MB have sound card and Ethernet integrated.

So how did those riser slots benefit a computer?

Reply 1 of 3, by Grzyb

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I've got some AMR modems, so it wasn't a completely dead standard.
But such cards weren't common, either.
In general, I consider such slots as a failure - the space used by them is much better used for another general-purpose slot.

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść no moja górę, lecz i w tym, ze ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 2 of 3, by Tiido

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Those slots are supposed to give you option for cheaper winmodem type thing. I see them a lot on PIII era motherboards but never actually populated. People here seem to have got a real modem or a cheap winmodem instead.

I have one AMR and CNR card but those were never used by me and I doubt they ever saw use in the machines they came from either...

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 3 of 3, by waterbeesje

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Same here. I see the slots quite often but they are rarely populated. I also have four models that fit either amr or cnr, but I haven't used them as well. These cards came in with some boards as a set.

Stuck at 10MHz...

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