Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site cornell.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!houxm!houxz!vax135!cornell!jqj From: jqj@cornell.UUCP Newsgroups: net.lan Subject: ground reference on Ethernets Message-ID: <403@cornell.UUCP> Date: Tue, 21-Aug-84 07:34:48 EDT Article-I.D.: cornell.403 Posted: Tue Aug 21 07:34:48 1984 Date-Received: Wed, 22-Aug-84 01:31:48 EDT Sender: jqj@cornell.UUCP Organization: Cornell Univ. CS Dept. Lines: 16 From: jqj (J Q Johnson) Cornell Engineering is in the process of designing a large Ethernet configuration spanning 10 buildings on the Cornell campus. Our plan is the traditional 500m backbone, with repeaters in each building connecting to an in-building segment. Concern has recently been raised about the differences in ground reference potential between buildings. Does anyone out there know whether differences in ground reference between two different controller/transceivers on an Ethernet are likely to cause degradation in the network? What is the maximum allowable difference in ground reference? My Blue Book does not discuss this issue directly, though some of the discussion (notably sects. 7.6.3, 7.4.3 and 7.2.4) leads me to believe that a moderate difference in ground might be acceptable. Anyone out there have experience or advice?