kroh wrote:
>
> Hello everybody.
>
> I'm going to hide a non-linux-specific arcnet question inside of a
> possibly linux-specific arcnet question. Hope no one minds. :)
>
> First of all, the linux-specific (possibly) one:
>
>
> sub arcnet_question { # see - one question!
>
> How picky are old arcnet cards?
> I just want to do point-to-point - what do I need?
> Finally - (okay, 2 unrelated questions. I lied) - assuming I can't build
> the things I need (terminators, t-connectors - I'm very resourceful ;) )
> does anyone know where I can find arcnet equipment? Used, preferably.
> Cheap - even more preferably. Possibly in the Houston area? I have these
> 4 8-bit cards, and, in the future, I want to put them to use by making an
> arcnet cluster at home here, then bridging it to the rest of my lan.
>
> Any help is appreciated!!!
>
First -- I've never used ARCnet with Unix so leave the first part of
your question to better minds than mine.
Second -- In theory, ARCnet is suppose to work with RG-59/U (75ohm),
RG-11/U (75ohm), RG-62 (93ohm), telephone-type twisted pair (100ohm)
and the old IBM Type 1 (150ohm). Personally I've never seen anything
but RG-62. Using RG-62, it can be wired in a bus or star or a
combination of the two. There were two types of hubs for the star
topology -- active (electronics needing power) and passive.
The easiest method is a simple bus using BNC T connectors at each
station and with BOTH ends terminated in 93ohms. Again, in theory
this should be a 93 ohm impedance (Z) but I've made workable
terminators using a BNC coupler and putting a 93 ohm resistor in one
end. Unlike ethernet coax buses, ARCnet must be terminated at both
ends.
You could make a simple, 4-port passive hub: port 1
|
|
port 2-----O------port 3
|
|
port 4
where each "spoke" is a 46-47 ohm resistor. Unused ports MUST be
terminated with 93 ohms. Maximum distance from a passive hub (to a
workstation) is 100 feet and passive hubs can be connected to each
other.
Have you checked SMC's Web site??? You should be able to find more
than you ever want to know about
ARCnet there <g>.
Have fun....
......Bill Sneed, Prospect, Maine.....
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