Xref: utzoo comp.dcom.modems:3600 comp.protocols.appletalk:1680 comp.sys.mac:28693
Path: utzoo!attcan!uunet!lll-winken!ames!pasteur!ucbvax!decwrl!labrea!dudevoir@isl.Stanford.EDU
From: dudevoir@isl.Stanford.EDU (Glen P. Dudevoir)
Newsgroups: comp.dcom.modems,comp.protocols.appletalk,comp.sys.mac
Subject: Re: Liason network bridges vs. Telebit TrailBlazer Plus modems
Message-ID: <411@isl.stanford.edu>
Date: 19 Mar 89 20:15:57 GMT
References: <22320@coherent.com> <1422@ccnysci.UUCP>
Sender: dudevoir@isl.Stanford.EDU (Glen P. Dudevoir)
Reply-To: dudevoir@isl.stanford.edu (Glen P. Dudevoir)
Organization: Stanford University
Lines: 48

In article <1422@ccnysci.UUCP> alexis@ccnysci.UUCP (Alexis Rosen) writes:
>In article <22320@coherent.com> dplatt@coherent.com (Dave Platt) writes:
>>According to the "Mac the Knife" column in the 3/14 issue of MacWeek,
>>there's a design peculiarity in the Liason network bridge software that
>>can have severe repercussions if you use this software with a Telebit
>>TrailBlazer Plus.
>>
>>It seems that the software periodically sends a modem-configuration
>>command string to the modem.  According to the article, this occurs once
>>per minute [etc.]   This
>>configuration command includes an "&W" sequence, which instructs the
>>modem to write the configuration information into its nonvolatile
>>memory.
>>
>>The TrailBlazer Plus's nonvolatile memory is (according to the article)
>>implemented in EEPROM, which has a life expectancy of 10,000 write
>>cycles.  At 1 write per minute, Liason could run through this lifecycle
>>in less than a week!  The results would be bad... you might find
>>yourself unable to change the configuration of your TrailBlazer, or find
>>that the modem had gone entirely belly-up due to inconsistent EEPROM
>>settings.
>
>THIS RUMOR IS ENTIRELY FALSE.
>
>I don't know how "Mac the knife" heard this, or why MacWeek was irresponsible
>enough to print this without verifying it. Liason is an extraordinary
>product, and this rumor may cause great damage to a company which is doing
>wonderful and unique things for Mac networking.
>
>To Summarize: your Telebits are not at risk.
>
>The detail: That command string is necessary to make the modem remember to
>autobaud. Telebits are shipped so that they default to high-speed mode, which
>is not what you generally want for a bridge. The write-to-prom command is
>given ONLY on reset, which generally happens when you reboot your mac. If
>
>Alexis Rosen
>alexis@ccnysci.uucp

You haven't explained why the modems are not at risk.  If the &w
command is given once a minute to insure that the modem autobauds then
the result predicted in the column is correct.  I should also point
out that the same is true for Hayes modems.  Either the software gives
the &w command once a minute or it doesn't.  Which is it?
I would like to know since we are considering the purchase of this
product for use with hayes modems.

Glen