From: reginald.hirsch@yob.sccsi.com (Reginald Hirsch) 
Newsgroups: comp.dcom.modems
Subject: THE ISSUE OF AN ALL MAIL
Date: 23 Jan 93 06:53:00 GMT
Distribution: world
Organization: Ye Olde Bailey BBS - Houston, TX - 713-520-1569
Reply-To: reginald.hirsch@yob.sccsi.com (Reginald Hirsch) 

TO: ed.hopper@ehbbs.gwinnett.com (Ed Hopper)
  Here's what happen to Garfield's message that was tossed.
Date: 01-23-93 (00:03)              Number: 374 of 374
  To: BILL GARFIELD                 Refer#: NONE
From: UUPCB MAIL                      Read: NO
Subj: UNDELIVERABLE MAIL            Status: RECEIVER ONLY
Conf: SPECIAL (300)              Read Type: GENERAL (+)

Re: Message #:1288
Your message below could not be transmitted.  You must include
an Internet address preceded by 'TO:'.  For example:
TO: user@machine.domain
Please examine the BBS bulletins on 'HOW TO SEND INTERNET MAIL'
if you have further questions.

Sincerely,

yob!uucp
------------------------------------------------------------------------

I recently purchased, for personal use,  one of the ZyXEL U1496+
models and then had the X+Y pattern generator option added.  (firmware
rev 5.02)

My employer, a major energy company headquartered in Houston, TX also
just acquired a pair of ZyXEL U1496-E models for evaluation.  (firmware
rev 5.04) I am one of the persons participating in that evaluation.

I have observed the following abnormality in both the "E" models as well
as in my own "S+".   With _default values_ in NVRAM except _&K1_ stead
of the default _&K4_ I have observed frequent link negotiation problems
where the ZyXEL modem fails to agree on the error correction method.
They may eventually connect, but will report "NONE" as the e/c method.

With _*E1_ in NVRAM along with _&K1_ the two modems, having failed to
agree on error correction protocol will disconnect - this of course is
normal with _*E1_ set. -but my point is, the e/c negotiation process
SHOULD HAVE been successful.  It was not.

I have observed this only when the ZyXEL is the _ORIGINATING_ device.
The host device does not seem to matter, as I have seen this failure
using several hosts, including Multi-Tech, USRobotics, and even another
ZyXEL.  Further, this abnormality has been observed in the ZyXEL only
when _&K1_ is set in the ZyXEL's NVRAM.

Why would anyone specify _&K1_ stead of _&K4_ you might ask?  A logical
question. The answer is because &K1 forces the link to use MNP, and
"MNP-4" error correction appears to be slightly more efficient than
"LAP-M" error correction when transferring pre-compressed (ZIP) files.
Since a v.42 link negotiation sequence defaults to LAP-M, one has to
force MNP-4 by setting &K1.  Unfortunately, the ZyXELs don't seem to
like this.

Setting _&K1_ in the ZyXEL nvram will not cause the error correction
protocol negotiation sequence to fail *every* time, but it does seem to
happen annoyingly often. Considerably often enough that this might be a
disqualifying factor if no satisfactory resolution can be found.

Yesterday I obtained the various ROM images for rev 5.05 firmware
and promptly burned some proms and installed them in the modems. 5.05
seems terribly buggy however as now all my ZyXELs suddenly seem to
dislike linking up with just about anything _except_ another ZyXEL.
I've seen this problem in 5.05 with 3 ZyXELs at my office and an
acquaintance who has a U1496+ like mine is also having problems with
firmware rev 5.05.  We changed back to 5.04(f) and the modems are all
back to working again, save for the minor forced-MNP negotiation
problem.

Has anyone else seen this problem with ZyXEL brand modems?  Does
anyone know if the factory or 0/1 Networking is aware of or looking
into this?  I would also appreciate hearing from anyone else who is
doing or has done evaluation studies of the ZyXEL U1496 family of
modems.

Thanks in advance.

Bill Garfield <bill.garfield@yob.sccsi.com> |  Std. disclaimer applies.
PBX/DataCom Engr.                           |  Opinions are my own and
Panhandle Eastern Corporation               |  not those of my employer.
Houston, Texas                              |  Nothing is implied.  I
Voice: 713.627.5228                         |  speak for no one other
Fax:   713.627.5285                         |  than myself.
Data:  713.520.1569                         |


Thanks
                          
----
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Newsgroups: comp.dcom.modems