>> The release note of "ULTRIX and UWS Version 4.3" has a definite figures
>> describing how DECsystem 5100 serial ports are labeled.  The point is,
>> 5100 port numbering is twisted and it's very hard to understand w/o
>> figures.
>> 
>> Figure 2-1 tells, facing to 5100 backplate there are three DEC MMJs
>> and one DB25.  ULTRIX does number them as "3, 1, 0, 2" from left to
>> right.  DB25 is numbered 2 and the doco tells modem capable.  The MMJ
>> left of it is 5100 console and numbered 0.
>
> Yes, that's it. But it's labeled '3' on the box (the MMJ are labeled 1,2,3
> on the box from left to right, no label for the DB25).

I'm uncertain that DEC changed the numbering scheme (or even retooled
5100 hardware) after the doco (AA-ME85-H-TE, August 1992) was
released.  If it describes 5100 correctly, it's clearly too confusing.
On page 2-10 section 2.6.1 "Backplate Labeling" starts as;

"The factory labeling of the console and terminal ports on the backplate
of the DECsystem 5100 does not refer to the device major and minor numbers
of the device special files made in installation time."

This pargraph and the following figure implicate 5100 backplate had no
label at least the doco was prepared.  Does anyone out there have
newer ULTRIX release notes?

Tohru Nishimura