🚀 go-pugleaf

/* Written  5:50 pm  Oct 28, 1985 by eric@unmvax in ICO:net.dcom */
/* ---------- "Thin Ethernet - (Any Specifications?" ---------- */

  > Does a standard exist for the so call "thin Ethernet" which
  > is getting more and more press these days.  This has the same
The draft of the IEEE 802.3A standard for 10BASE2 (cheapernet or thin
ethernet) was approved by the IEEE Standards Board at their June 85 meeting.
It should be circulating within the ISO group by now.  You can order it
from IEEE for $6.00.  The announcement went out a while back since ANSI has
adopted it also.  IEEE/802a is a supplement to the ANSI/IEEE 802.3-1985 standard
and can be ordered from:
	IEEE
	345 East 47th St.
	New York, NY 10017-2394
	Attn: Sandra Phillips

This should be what you want.
			
			Doug McCallum
			Interactive Systems Corp.
			{cbosgd, hao, ima}!ico!dougm

In article <943@unmvax.UUCP>, eric@unmvax.UUCP writes:
> ... Is there a standard for this "thin ethernet"
> or a group that backs it with published specs, such as DEC-INTEL-XEROX
> group that backed the standard Ethernet?


As this is probably of interest to many, I've posted this article.

To the best of my knowledge, there is no published spec for RG-58. However,
after months of research, here's what we've come up with:

	A "segment" (Thick or RG-58) can support a mximum of 100
nodes of MAUs. A segment may be composed of one or more lengths of
cable. Using thick cable, each segment has a maximum length of
500 meters (1640 feet). With RG-58 this maximum is reduced to 152 meters
(500 feet[!]). The difference is capacitance and signal loss. The
formula to use is:
	T * 3.28 + E = 500 meters
where T= length of <T>hin and E= length of <E>thernet (thick).

Transceivers are ALWAYS required, it's just that using RG-58 it is
reasonable to use on-board transceivers such as 3Com, etc. It is just
as legal to connect thick cable to a thick-to-thin adaptor, through
the T, and back to thick cable again...but the big yellow stuff
would probably bust the T!  Likewise, you can use a transceiver with
BNC connectors and run a transceiver cable from the RG-58 net to
the standard 15-pin IEEE 802.3 connector.

(Another difference between Thick and RG-58 is the velocity, of
course. Thick cable is 0.77c while RG-58 is somewhat slower, perhaps
0.65c or less.)

Now, how come some folks (3Com in particular say "run 1000' with
RG-58"?  They cheat!  As best we can tell, their transceviers put out
a signal level greater than that of the IEEE802.3 standard.  This
means that a network with ALL 3Com can be 1000' per segment. BUT (!)
if you put any other transceiver on the net, look out! We never go
beyond the 802.3 specs in our installations.

Anyone needing more info can reach me through the net.

	Doug Kaye
	Rational Data Systems
	5725 Paradise Drive
	Corte Madera, CA 94925
	ihnp4!hplabs!well!drk <doug kaye>