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Are AUI to AUI Null Cables Possible?
Mike Harvey
asks: "Hi, after obtaining a SparcStation 1 I realized
I have no way to connect it to my network. I know I could
go out and buy a transceiver for it, but, as one of the
really poor students of the world, I was wondering if it
was possible to do an AUI to AUI null (or crossover) cable,
and whether it would work to connect it to a second net
card in one of the other computers? I could just try it,
but I would prefer not to make either into paperweights."
There are companies out there who specialize in the removal of obsolete computer equipment. You might try them for the tranceiver, or the AUI cable you actually need.
Any driver should work fine in full-duplex mode...
If you get two $5 NE2K clones and a cross-cable, then hook them directly, you'll be in full-duplex mode - works fine.
As far as loopback - this only applies to 10Base-2, where the AUI transceiver has lots of circuits to explicitly drop loopback current so the card/driver etc. doesn't even see it!
Besides - even if it didn't work, the worst that can happen is that it doesn't work. I'm sure anyone clueful enough to build the cable could run a couple of pings and check the link out. If it doesn't work, then you've wasted $10 on cabling and have to go by a transceiver. If it does, then you've just saved lots of money...
Others have given probable wiring diagrams, so I won't attempt to repeat them. At work a few years back I did this, someplace we found a AUI-AUI null cable, and it worked fine. If there were any extra parts they all fit inside a cable hood. I didn't wire it, I just used it.
Most importantly it worked, so if you feel like putting it togather it can work.
... at least on my SS10. The connector is not the familiar DB15 it is on PC hardware, it's more like a dense female 25 pin, very much like the Sun speaker connector. However, I am not really familiar with Sun hardware, so don't take my word for it.
:wq
I think an xcvr would be easier, too, but a quick look at a pinout list makes me think it'd be possible. I haven't tried it; I can't recall the last time I saw an Ethernet AUI port. IANAEE (Electical Engineer), YMMV
I don't mean to be snotty but, get a transciver...
Actually, go to your uni's network/computer dept. staff and ask for an old one, I bet you they have lots just lying around...
It's the only sane way to get any use out of the old relic....
/olle
Acch!! Pfft!! Obviously, I didn't mean a mailing list - it's from an old Usenet post in comp.dcom.lans.ethernet.
Found this on a mailing list - hope it helps (but it really would be easier to just buy a transceiver).
Ethernet AUI to AUI cheaply
Take a look at the auctions and find a cheap transceiver. If you have ancient AUI hardware, then you probably wouldn't mind used transceivers either. They'll run you about $10 or so a piece, which is about what 10baseT netcards run at swap meets, etc. If you are in the Dallas, TX area, take a look at first saturday (www.1stsat.com), but the things happen in most big cities.
Look for old stuff that no-one wants, but are still useful -- unlike AUI cards. If you are looking for it for a sun machine, I can sympathize with you, though.
I looked at the wiring diagram posted above and noticed a few things:
1. There is no feed-back capability, thus the machine in question will not receive its own packets. This is a violation of all the IEEE rules and will likely reek havoc on all but the most stable IP stacks.
2. The collision detection pin is diliberately grounded, thus this is a FULL DUPLEX connection.
Both points can be handled IF AND ONLY IF you can configure the device driver to accept a full-duplex configuration, which is unlikely for a driver meant to work across an AUI. You may find that it works, sort of, under light load.
I agree with the other posts, the transceiver is the best alternative. The microtransceivers are running $35 or so, retail.