Re: Cap 60/pl126 and Personal Laserwriter NTR

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#3508

From: Dave Platt
Date: Thu, 31 Dec 1992 01:54

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>>                                       The NTR is visible
>>from a mac's finder but not from atlook/atlooklws or lwpr.
>>What is going on?
>
>I have encountered the same problem running CAP 6.0, pl126, phase 2,
>on a Sun SPARCstation 2 with SunOS 4.1.3.  I am able to see several
>different kinds of printers (IIg, NTX) but not the Personal LaserWriter
>NTR.  If anyone has an explanation for this, please post it to the group.

Cause:  the LaserWriter II NTR does not calculate DDP checksums
properly.  Macs do not bother verifying DDP checksums;  CAP does.  CAP
is discarding the packets sent by the NTR on the reasonable assumption
that they have been damaged in transit.

Cure:  upgrade to CAP 6.0 pl125.  You can disable DDP checksums
entirely, but it's better to simply run atlook, atlooklws, lwsrv, and
so forth with the -k option which selectively disables DDP checksum
validation on a connection-by-connection basis.

Other printers affected:  some Tektronix Phaser printers, and some QMS
printers, also exhibit this problem.

Other steps required for fix:  if you are using a FastPath running
K*Star as a gateway between Ethertalk and Localtalk, you must disable
DDP checksum validation in K*Star.
-- 
Dave Platt                                                VOICE: (415) 813-8917
              Domain: dplatt@ntg.com      UUCP: ...netcomsv!ntg!dplatt
 USNAIL: New Technologies Group Inc. 2470 Embarcardero Way, Palo Alto CA 94303

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Message-ID: <1992Dec31.015404.1517@ntg.com>

Path: arc1-ca.pugleaf.net!sparky!uunet!think.com!spool.mu.edu!olivea!apple!ntg!dplatt

References: <1992Dec28.004953.22588@dartvax.dartmouth.edu> <8266@lib.tmc.edu>

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Path: arc1-ca.pugleaf.net!sparky!uunet!think.com!spool.mu.edu!olivea!apple!ntg!dplatt
From: dplatt@ntg.com (Dave Platt)
Newsgroups: comp.protocols.appletalk
Subject: Re: Cap 60/pl126 and Personal Laserwriter NTR
Message-ID: <1992Dec31.015404.1517@ntg.com>
Date: 31 Dec 92 01:54:04 GMT
References: <1992Dec28.004953.22588@dartvax.dartmouth.edu> <8266@lib.tmc.edu>
Distribution: usa
Organization: New Technologies Group, Inc.  Palo Alto CA
Lines: 29

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