🚀 go-pugleaf

In article <2799@ttrdc.UUCP> levy@ttrdc.UUCP (Daniel R. Levy) writes:
>In article <407880.880706.KFL@AI.AI.MIT.EDU>, KFL@AI.AI.MIT.EDU ("Keith F. Lynch") writes:
># > From: "Benjamin I. Goldfarb" <goldfarb%hcx9%ucf.CSNET@RELAY.CS.NET>
># 
># > OH YEAH?  More likely the "UUUUUUUUUUU" was an erroneously
># > initiated test mode in the modem in question.  Racal-Vadics are
># > notorious for this ...
># 
># My Hayes 1200 gets into this mode once every few dozen hours of use.
># It doesn't seem to correlate with what I'm doing.  It sends a bunch
># of UUUUU to the host, and locally echos anything I type.  I can't
># find a way out of it except to turn it off and on again.
>
>I've also had this happen with my (Hayes-commandalike) Anchor Automation
>Volksmodem 12.  Similar to the Hayes described above, I see UUUUU... on the
>screen and then it begins to locally echo.  Weird.
>-- 
>|------------Dan Levy------------|  THE OPINIONS EXPRESSED HEREIN ARE MINE ONLY
>|    AT&T  Data Systems Group    |  AND ARE NOT TO BE IMPUTED TO AT&T.
>|        Skokie, Illinois        | 
>|-----Path:  att!ttbcad!levy-----|

Sounds like something is forcing the modems into a test mode. You are 
not really seeing U's on the screen.  What you ARE seeing is a mark/
space test pattern (01010101) that just happens to be the same as an
ASCII 'U'.

If I remember correctly, the self test pattern is generated by what 
is called a 'analog loopback test' which tests the analog receiver
and transmitter circuitry.  This test usually disables the digital 
interface and the repeating pattern doesn't appear on your screen.

There is another test that modems sometimes run called a 'digital' 
or 'local' loopback which tests the digital part of the unit.  The 
test runs by taking whatever it receives on the TX line and turning
it around and back out the RX line.  It sound like this test may be 
running when you the modem is echoing locally.

There are special codes that one can send a modem to put it into 
test modes remotely.  It sounds like perhaps these units are
recieving what they believe to be these codes.