Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!psuvax1!rutgers!cunixf.cc.columbia.edu!cunixb.cc.columbia.edu!ab4
From: ab4@cunixb.cc.columbia.edu (Andrew M. Boardman)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Why do mysterious UUUUUUUUUUUUs sometimes dance on my screen?
Summary: Marching Umber Hulks...
Message-ID: <1990Nov12.084729.16629@cunixf.cc.columbia.edu>
Date: 12 Nov 90 08:47:29 GMT
References: <9011111530.AA10882@ucbvax.Berkeley.EDU>
Sender: news@cunixf.cc.columbia.edu (The Daily News)
Organization: Quiche Eaters Anonymous
Lines: 6

There was a an exhaustive discussion of this a while ago, in, I believe,
comp.dcom.telecom.  I seem to remember that this was caused by modems
trying to resync -- they would send alternating 1's and 0's until they
got back on speaking terms.

/a