Path: utzoo!dciem!trigraph!john
From: john@trigraph.UUCP (John Chew)
Newsgroups: comp.protocols.appletalk
Subject: Re: Need info on talking from unix to LaserWriter through FastPath
Message-ID: <439@trigraph.UUCP>
Date: 23 Feb 89 15:24:27 GMT
Article-I.D.: trigraph.439
References: <172@amtfocus.UUCP> <837@wpi.wpi.edu>
Reply-To: poslfit@gpu.utcs.UToronto.CA (John Chew)
Followup-To: comp.protocols.appletalk
Organization: Trigraph Inc., Toronto, Canada
Lines: 63

In article <172@amtfocus.UUCP> troym@amtfocus.UUCP (Troy Monaghen) writes:
>We are running a Motorola Delta series computer with System V R3 unix and
>have a need to talk to our LaserWriter on LocalTalk through a FastPath 4.
>If anyone has any information on how to do this please send me mail.  I am
>interested in just about any kind of information including source code,
>books or anything else that might help.

Sounds to me like you need a copy of CAP (Columbia AppleTalk Package),
a Un*x AppleTalk library that comes with various useful programs which
query laserwriter status, send individual files to a laserwriter, or
set up a laserwriter spooler.  Try your nearest archive site.

>Also, does anyone know why the LaserWriter seems to prevent anything from
>working on the LocalTalk network when it is switched from "AppleTalk" to
>"9600 baud".  When we do this (so our unix box can print on it through the
>serial port) our MAC's running TOPS suddenly no longer talk to each other
>until the LaserWriter is either switched back to AppleTalk or the LocalTalk
>cable is unplugged from it.  Is there any way around this?

To which tron@wpi.wpi.edu (Richard G Brewer) responds
  in article <837@wpi.wpi.edu>

>As I recall, the switch in the back deactivates the AppleTalk port when
>switched to the other settings (as it can only manage ques from one port at a
>time). I imagine that this terminates the "chain" in the Appletalk network,
>dividing it into two parts. This is just a guess, though...

... but not a correct guess.  The little LocalTalk connector box is
there to allow you to disconnect individual nodes without separating
the network.  When this happened to me a few weeks ago, after the
customary hour or two of banging my head against the wall without
inspiration, I decided to RTFM, not the "Apple LaserWriter II NT/NTX
Owner's Guide" that comes with the printer, but Apple's "LaserWriter
Reference", the Addison-Wesley hardcover.  Appendix A (Serial-Data
[sic] Communication) states that when a LaserWriter is in serial
mode, both ports (DB-9 & DB-25 or DIN-8) are active and "The first
channel to receive a character is chosen to execute the job."  So
as near as I can tell, if you are still connected to LocalTalk, the
first burst of traffic on the net will confuse the LW into thinking
it has received a garbled serial character, sending out a welcome
message, a prompt, and worst of all, echoes onto the unsuspecting
network at 9600 bps.  

(mild flame)
Now while I think it's just peachy that the LW series can perform
two-channel job arbitration in serial mode (does anyone really use
this feature?), I think (1) it would be nice if this were mentioned
somewhere in the LW Owner's Guide and (2) it would be REALLY NICE
if you could tell the LW not to listen to the LocalTalk port when
in serial mode, as I could then just use setsoftwareiomode and
sethardwareiomode to switch modes without having to walk over to
the LW and swap cables.
(emalf)

So anyway, the moral of the story is: you can't have a LW physically
attached to a LocalTalk network when in serial mode.

John

-- 
john j. chew, iii   		  phone: +1 416 425 3818     AppleLink: CDA0329
trigraph, inc., toronto, canada   {uunet!utai!utcsri,utgpu,utzoo}!trigraph!john
dept. of math., u. of toronto     poslfit@{utorgpu.bitnet,gpu.utcs.utoronto.ca}