Hardware/Software expertise, anyone?

[Michael Dahl]

> I am looking to hear from anyone that has looked at the back of an ALM-2
> and figured out what it takes to use that port marked "printer". What is
> the underlying hardware implementation (parallel/serial?). What sort of a
> /dev entry does it use? What gets added to the kernel to use it? Is there
> an FM I should read?
> 
> P.S. 3/260 , 16M, SunOS4.1

I have been through this exercise.  I never got it fully working, but here
is a summary of what I found out.  

The ALM-2 has a parallel printer port.  A pinout for the printer port can
be found on page 30 of the 16 Channel Asynchronous Line Multiplexer-2
Field Service Manual and Installation Notes that should have come with
your board.  Also see Section 8 starting on page 39 covering Printer Port
Loopback Diagnostics.

As per Appendix A, when you give the MAKEDEV mcp0 command, you will also
create a /dev/mcpp0 device which is for the parallel printer port.  If
memory serves me, you should be able to use a standard PC parallel printer
cable to hook up your printer.

I hooked everything up and then tried a "cat testfile > /dev/mcpp0" The
testfile had 4 lines in it, but only 2 lines came out on the printer.  A
larger file seemed to come out ok, but I didn't look that close.  I never
got any further than this, as we received an IBM RS/6000 with a parallel
port that was already configured and worked without problem.  

All of this was using SunOS 4.0.3.  It may work better in 4.1.  To be
fair, I never did call Sun support on the problem to see if they could
help.

Hope this helps.

Michael Dahl,  Cimplex Corporation  
Voice: (408) 879-2800  Fax: (408) 879-9605
1500 E. Hamilton Ave. Suite 100,  Campbell Ca. 95008 
dahl at netcom.uucp  - or -  {apple,claris}!netcom!dahl