Ethernet over coaxial?

[redrumloa]

It can be done right? Where does one find adapters?

[elendil]

back in the days without twisted pair it worked, at least

and afaik in exactly the same way as TP. I am not sure I understand your question completely. You will need an ethernet board and if it has not got a coax connector it would be cheaper to buy a TP cable than some sort of adaptor.

Again: I am not sure what you are asking exactly, so feel free to enlighten me, if I am not making any sense

Sincerely,

-Kenneth Straarup.

[iamaboringperson]

im not sure what you want...

are you saying you want some sort of cat5/RJ-45 to coaxial adaptor? such a thing does exist!

its just two of the wires(one pair) going into the coax cable

of course, its only half duplex!!

Sure ethernet over coax is possible.   There are several ethernet standards.  10base2 uses thin coax (RG-58) and 10base5 uses thick coax (RG-8).   The coax used for most home cable/sat TV systems is RG-6 so its not the same as thick ethernet coax.  The other ethernet standard most everyone is familiar with is 10baset which is twisted pair cat-5 cable.

If you have a good reason why you can't use 10baset, I would check around online for either 10base2 or 10base5 NIC cards.  www.pricewatch.com is where I always start for computer hardware.

The benefit of using coax over twisted pair is coax offers greater cable length.  Regular 10baset cat-5 has a cable limit of 100m, 10base2 can go 200m and 10base5 can go 500m.

[ShadesOfGrey]

Here are a couple URLs of interest:

http://www.lantechuk.com/products/lan/converter/converter/10mb_converter.html
http://www.customcable.com/Connectivity/Media-Converters-tbl.cfm

[amigau]

two local sources here in the Seattle area are DataPro and Redmond Cable:

http://www.datapro.net/catalog.html
http://www.redmondcable.com/

either of which should have something like this for you.  

When I had a Hydra ethernet card in an old A3000D (sold it, the hub and coax all together last year) I used it with Miami and used the coax terminators I got with the two x-surf cards I have - it comes with them as it has coax output as well as the more usual (these days) RJ45.  So if you know someone with an x-surf, they should have at least one of these terminators laying around.

If you can find an older hub (ebay) they often had ONE coax junction with the other usual 4 or 8 RJ45, which is what I used with my old computer - I sold the hub with that computer to allow the buyer to network without hassle.  You have to terminate each end, the end that hooks to the computer, and the end that hooks to the hub, on the assumption you have only one coax computer on the network (otherwise you can 't' into the back of at least one of them without terminating it).

kevin orme
amiga university
www.amigau.com

[tonyw]

Don't try using "TV" cable - it's 75 ohm impedance and Ethernet is 50 ohms. If you use 75 ohm cable you'll get all sorts of nasty reflections and probably no workee.

Like SCSI, Ethernet coax must be terminated at each end of the cable, with a 50-ohm termination. There must be exactly two terminators, one at each end, none in the middle.

tony

[Floid]

"Run one pair" to the coax?  Huh?

Anyhow, hubs with a 10base2 'uplink' can be found from PCBay.  Note that those are FCC Class A, meaning "they could use some shielding" -  using them at home did give cause me a little localized TVI that I really should've done something about.  (A little bit of patterning on off-air channel 5, with the coax run ungrounded and strung close to the antenna.  Probably nothing that'd bother neighbors.)

If your network card has an AUI connector (DB15), you can find an external transceiver cheap on eBay.  Search for "thinnet transceiver," "10base2 transceiver," etc.  You might also find a more bulletproof hub.

If your card doesn't have an AUI or BNC connector, and we're talking x86-land here, it's cheapest to just find one that does.  I like old ISA cards based on the Realtek 8019(AS?), which is about as high-performance as an NE2000 clone gets.

You can also scrounge true plug'n'play UTP <-> 10base2 bridges/repeaters on eBay.

If you're thinking about recycling television wiring as 10base2- no, it's not the same stuff, but you can sneak by if you're not concerned about potentially sacrificing your cards/hubs.  Here's a newsgroup thread on the topic, and another post by someone suggesting a termination technique.  I wouldn't risk any rare-classic-Amiga-hardware to such a setup, but with two Ark/Noname hubs on each end, it's a possibility.

Other neat ethernet tricks include recycling unused phone pairs for 10baseT, as I said elsewhere (presumes your location was wired with decent-quality CAT3 cable), and then there's HomePNA and HomePlug and wireless to choose from...

[Ilwrath]

I run my C= card in the 10base2 coax cable.  I had a hub with that as the uplink, and simply wired it to the hub, rather than using a 10baseT transciever.

If you have a hub with a 10base2 uplink and a network adaptor (card) that is 10base2 (like the original C= Amiga network card) all you need is a length of 50ohm coax, 2 T connectors, and 2 50ohm terminators.  

Screw one terminator on each T connector
Screw the coax between the two T's
Screw one T to your hub, and one T to your network card.  (remembering to set any necessary jumpers on the network card to tell it you're using coax!)  
Test network -- you're done.

I found this configuration ran quite a bit faster on my Amiga than my former X-Surf...

[Waccoon]

Make sure you have plenty of spare cables.  I used to be a network administrator for a fleet of Macs linked with coaxial cable.  If one connection comes loose or a cable goes bad, the whole network goes down.  Eventually, the school gave me some money to rewire the network, and I updated everything to twisted pair with two hubs.  Problem solved.   :-)

[redrumloa]

Thanks for all the responses! I am going to be upgrading an arcnet network to ethernet and using the existing coaxial would be the easiest route.

Anyone know off the top of their head what flavour coxial arcnet uses?

[Desmon]

@redrumloa

It can be done right? Where does one find adapters?

On the Amiga side, there's the A2065 or if you're lucky enough to find one the A4065. For the PC, most RTL 8029 cards have the BNC connector you're looking for. You will need terminators   and "T" pieces as well. Each card will need the T and both ends of the cable will need termination. (not unlike SCSI does) Make sure the cable is rated at 50 ohms as well as each terminator.

As to finding all the pieces, try your local electronics store.

[Desmon]

@redrumloa

Thanks for all the responses! I am going to be upgrading an arcnet network to ethernet and using the existing coaxial would be the easiest route.

Anyone know off the top of their head what flavour coxial arcnet uses?

Dinna see this one before the last reply.

The easiest way to check what you have already is to look carefully at it. If the original terminators have a "50" marked anywhere on 'em, I'd just re-use the whole lot. The cable itself should be marked as well, but it's probably a little harder to see after a few years in use.

[Floid]

redrumloa wrote:
Thanks for all the responses! I am going to be upgrading an arcnet network to ethernet and using the existing coaxial would be the easiest route.

Anyone know off the top of their head what flavour coxial arcnet uses?

RG-62, with an impedance of 92 ohms.
Which feels like a bit of a stretch for 10base2.  If you're dealing with a home or extreme-SOHO setup, you could see how things fare with 50 ohm terminators and the aforementioned disposable hubs, but if this is anything 'real' - meaning intended to be relied on at all - you'll need to find some true media converters, which probably won't come cheap.  (Google's not being helpful for me tonight.)

I find one reference to Windows offering Ethernet-over-Arcnet encapsulation, a trick that could probably be performed by Linux or *BSD as well... that'd imply sticking with the existing Arcnet, and plopping tunnel endpoints on each end.  This would, of course, leave you stuck with Arcnet and its speed limitations, but at least you'd know you're in-spec and shouldn't need to plan for replacing impedance-mismatch-torched hardware.

Here's one hit for some more-appropriate hardware:
USENet thread mentioning media conversion hardware..
Be sure to read down to the next message, which elaborates on the 'unbaluns' that could be used as well.

Sounds like, if you've got a building/campus full of the stuff, you want to track down a bunch of the mentioned RG-62-capable hubs.  If it's just one point-to-point link, you might get by "reliably" with the cheapo Ark hardware, *and*  appropriate 'unbaluns.'  Or, if we're talking a whole building here, and tracking down enough of the RG-62-capable hubs is trouble, an all-10base2 hub/switch, *and* enough of those unbaluns for both ends, allowing one of the cheapo Ark hubs (or a machine with a 10base2 NIC) to be placed at each drop.

When you get to that last point, just about any alternative- pulling CAT5, deploying wireless, buying a few overpriced HomePNA bridges and recycling existing phoneline- starts to sound good.

[Floid]

I did find one Google hit for the 'unbaluns.'  You'd have to order from Germany, but maybe it's still cheaper/saner than other possibilities for your application.

Edit: ...and note that you need a true "media converter" (or a hub) to go between 10baseT and 10base2.  You might come across 'dumb' baluns that can use UTP as the equivalent of coax for 10base2 networks, but they can't magically turn the differential signals of 10baseT into a signal that can travel over coax.  (I don't know where you or anyone else is coming from in this thread, so... as a basic identification metric: if it has blinkenlights and/or requires power, it's not 'just a balun.'  If it doesn't require power, it probably is.)