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From: rar@balungan.west.sun.com (Rob Rosen - Northwest Area Consulting)
Newsgroups: comp.sys.sun
Subject: Re: How can I revive a lost ethernet carrier?
Keywords: Networks
Message-ID: <1990Aug13.005903.3810@rice.edu>
Date: 9 Aug 90 06:27:39 GMT
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X-Sun-Spots-Digest: Volume 9, Issue 293, message 7
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>In article <1990Aug3.002136.4033@rice.edu> lindy!romeo@lindy.stanford.edu 
>(Patrick Goebel) talks about problems with a Cabletron 10BaseT MAU on
>a Sun 4/330.  My recommendation is to check the owner's manual for the
>Cabletron and/or whatever is at the other end of the twisted pair.
>
>AT&T's StarLan-10 devices have error indicators on each port that light up
>when a flurry of bad packets arrive on that port.  The port is disabled
>and stays that way so you can see the error light when you go grubbing
>around in the telephone closets looking for the problem.  You clear the
>error condition by cycling power to the PC that was misbehaving.  For
>workstations and servers, where cycling power is a major inconvenience,
>the device can be strapped to clear itself after about 20 seconds.
>
>Check with the Cabletron manuals; the MAU may have a similar option.

The Cabletron MIM (hub concentrator module) does indeed have a two LEDs
for every port; in addition, the TPT-T (10BaseT transceiver) has six LEDs.
If the LINK LED on the TPMIM-T is blinking, then the MIM has turned off
the node in question due to a physical-layer error somewhere, which is
usually a yanked AUI cable or miswired crossconnect.

If the LINK LED on the transceiver is not lit, then there is no signal
going between the transceiver and the MIM - check the UTP wiring and
especially the punchdown blocks.

	Rob Rosen 	Sun Microsystems, Inc.		Professional Services
Rob.Rosen@West.Sun.COM [Internet]     sun!rar [UUCP]     	415.781.8140