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From: borriell@aecom.yu.edu (Frank Borriello)
Newsgroups: comp.laser-printers
Subject: NEC LC890 Pageprinter Shortcomings
Keywords: serial ports NEC service
Message-ID: <9007120321.AA28460@crayola.cs.UMD.EDU>
Date: 25 Jun 90 19:26:32 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: Albert Einstein College of Medicine, NY
Lines: 34
Approved: laser-lovers@brillig.umd.edu



Although this may be redundant, I think it is worth warning anyone
contemplating purchase of the NEC LC890 LED printer for use as a serial
PostScript printer, that a serious design flaw makes this machine less than 
desirable.  Although advertised as an RS-232 standard device, this is 
absolutely not the case.  In fact it is a TTL port where the signals
vary from 0 to +5V and not -6V to +6V as RS-232 stipulates.  This is no
small point since if you use a computer which expects to see
RS-232 (notably SUN!) the printer will be invisible and not flow control
signals will be perceived.  At first I thought there was something wrong with
either the printer or my SparcStation 1+ serial port.  Checking with
test equipment showed that the printer port was weird.  A call to NEC
which took the better part of an hour to connect to someone who even
knew what a serial port was, confirmed that this is indeed a design "error"
(my adjective not his) and that the solution was to use the centronics
parallel port with a serial converter on the line.  Besides the added cost
of such a beast, this is unacceptable because the NEC parallel port is
receive only so that queries to the postscript interpreter are lost and
any software used which needs this feedback is negated.  On many computers,
this is not a problem since the ports are not sensitive to the voltage 
differences and thus will work fine (i.e. I used a UNIX PC for years
without perceiveing the defect).  However, as the relatively smug tech at
SUN pointed out, when you use a high quality machine like SUN (his adjective
not mine) which adheres to open computing standards like RS-232, then
you must use high quality peripherals.  Although I am kludging with the 
$90 converter, I think that NEC should have done something to make the 
machine do what it was sold to do - communicate with an RS-232 device!  Their
attitude showed me that NEC has no interest in end users and little pride in the
quality of thier product or their public image.  I therefore can only
warn users of SUN equipment that NEC laserprinters may not be compatible 
with thier ports!

ksk@kaecom.aecom.yu.edu