[comp.lang.postscript] LaserWriter simultaneous serial & AppleTalk

amanda@lts.UUCP (04/13/89)

In article <487@grand.UUCP>, Dave Yost writes:
>I have a LW+ (firmware 38.0) hooked up to a Sun through
>the 25-pin serial interface, with the selector switch set
>to 9600 (operating at 19200 baud).
[...]
>Does anyone know if this behavior is different with the
>newer (47.0?) LW+ firmware?

As I remember, the two connectors on a LaserWriter or LW+ are not
actually separate interfaces, but are simply wired together into
the printer's single serial port.  In other words, the same hardware
is used for AppleTalk and serial communication (a Zilog SCC).  This
means that the printer can be used in one mode or the other, but
not both.  In fact, attaching to both connectors at once is liable
to truly confuse the AppleTalk whenever a job is sent over the
serial line.  The fact that you are able to print jobs from the
serial line is because (a) that's what you have the switch set for,
so that's what the printer's serial port is programmed to handle,
and (b) I'll bet you don't have a very busy AppleTalk network...


Amanda Walker
InterCon Systems Corporation