Path: utzoo!attcan!uunet!maverick.ksu.ksu.edu!ux1.cso.uiuc.edu!uxc.cso.uiuc.edu!paul
From: paul@uxc.cso.uiuc.edu (Paul Pomes - UofIllinois CSO)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Why do mysterious UUUUUUUUUUUUs sometimes dance on my screen?
Message-ID: <1990Nov11.170858.9657@ux1.cso.uiuc.edu>
Date: 11 Nov 90 17:08:58 GMT
References: <9011111530.AA10882@ucbvax.Berkeley.EDU>
Sender: news@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 24

sherman%vsdec.decnet@NUSC.NAVY.MIL ("VSDEC::SHERMAN") writes:

>Hi.
>
>I've had/seen an intermittent problem over the last 8 years, and
>I have yet to bump into anybody who can explain why I see this
>problem, or what it is. 
>
>I'll be connected to some computer via modem doing my normal work
>when suddenly I'll get about 60 uppercase Us on my screen.  From
>then on, everything I type gets echoed on my CRT but I get no
>responses back from the computer that I'm connected to.

Some line noise is triggering the remote modem to go into a test mode and/or
loopback.  Upper case 'U' characters have an alternating 1-0 bit pattern
useful for testing BER, etc.  The fix is to disable remote toggling of test
mode.

/pbp
--
         Paul Pomes

UUCP: {att,iuvax,uunet}!uiucuxc!paul   Internet, BITNET: paul@uxc.cso.uiuc.edu
US Mail:  UofIllinois, CSO, 1304 W Springfield Ave, Urbana, IL  61801-2910