30 Dec
2001
30 Dec
'01
7:03 a.m.
On Sun, 30 Dec 2001 19:22:25 +0000 (GMT), Tony Duell wrote:
#> # Both of the
#> #centronics ports on the printer are SCSI. I've never seen one that has
#> #a parellel port.
#>
#> Well, you are mistaken about something. This printer has _three_ Centronics ports,
two are SCSI, and
the
#> other is smaller, the size of a parallel port. My theory is that this is the
difference between a Model 2004,
#> which is documented in web literature, and Model 2005, of which there may have been
few examples
(since
#> this one is evidently number 17).
#
#I've never seen this printer, but I think you're a little confused.
#
#The Centronics interface is a de facto standard for a parallel interface
#to a printer, as originally used by the Centronics company. It's not SCSI
#or anything related to it. To say you have a Centronics port that is SCSI
#is meaningless IMHO.
#
#What I think you mean is that you have 3 'blue ribbon' connectors on the
#unit. 2 are 50 pin (which was often used for SCSI-1 interfaces), the
#other is 36 pin (which is a standard for the Centronics parallel
#interface).
#
#My guess is that the 36 pin connector _is_ a Centronics parallel port,
#but I'd probably not just plug it in on such a rare printer without doing
#some further tests. One test that's easy to do is to trace which pins of
#the connectors go to logic ground (this is generally easy enough to find
#inside) and see if they match up with any known interface pinout.
#
#-tony
#
With all due respect, I disagree. The term "Centronics", whatever its original
meaning, refers to a type of
connector. Looking at the Jameco catalog, for example, the catalog pictures 14, 24, 36
and 50 contact
male and female connectors, all referred to as "Centronics". I have never heard
the term "blue ribbon" used
to describe these connectors.
My understanding is that Centronics was the first to use this type of connector on its
parallel printers, so
when it became the standard type connector the name stuck.
Parallel port nomenclature now has a number of different terms, based on function and
standard, not type of
connector. SCSI connectors are sometimes Centronics type, but not always.
In any event, the "36-pin Centronics Connector" is a parallel connection, and
the PC was able to talk to this
printer.
BTW, this type of connector, regardless of the number of pins, when made for ribbon
cables, is referred to
by Jameco as "IDC Centronics Connector".
Louis