Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site redwood.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!zehntel!dual!amdcad!fortune!rhino!redwood!rpw3 From: rpw3@redwood.UUCP (Rob Warnock) Newsgroups: net.lan Subject: Re: Ethernet Transceiver Cable question... Message-ID: <89@redwood.UUCP> Date: Sat, 1-Dec-84 10:28:55 EST Article-I.D.: redwood.89 Posted: Sat Dec 1 10:28:55 1984 Date-Received: Tue, 4-Dec-84 05:25:41 EST References: <326@rna.UUCP> Organization: [Consultant], Foster City, CA Lines: 25 There is no official minimum transceiver cable length. However, what you are seeing may be some interaction between the Interlan controllers and the DELNI. In particular, if one side is configured for Ethernet Version 1.0 and the other for 2.0, there is a spec on the "idle state" of a transceiver signal pair that may be causing trouble. The 1.0 units expect the other side to maintain a solid differential "1" when idle; 2.0 (and IEEE 802.3) specifies a "decay to idle" which is more-or-less an ECL "tri-state" (no differential voltage). Now if the "squelch" on the 1.0 side is set too low (or is missing), such a "tri-state" condition is a candidate for picking up noise, causing your erratic performance. Adding 50 feet of cable may put enough capacitive load on the lines that the noise problem goes away. Alternatively, there is a spec on the decay-to-idle time, which one side or the other may be violating in the absence of enough capacitive load. Rob Warnock UUCP: {ihnp4,ucbvax!amd}!fortune!redwood!rpw3 DDD: (415)572-2607 Envoy: rob.warnock/kingfisher USPS: 510 Trinidad Ln, Foster City, CA 94404