Re: OK, I need some help on this one...

Article: 7625 of alt.hackers
From: bdrake@bengal.oxy.edu (Barry T. Drake)
Newsgroups: alt.hackers
Subject: Re: OK, I need some help on this one...
Date: 7 Apr 1995 07:04:49 -0700
Organization: Occidental College, Los Angeles, CA  90041 - USA
Lines: 76
Approved: bdrake@oxy.edu
Message-ID: 3m3gq1$kdk@bengal.oxy.edu
Status: RO

In article <3li9op$hg5@access1.digex.net>,
Michael Lea <mikelea@access1.digex.net> wrote:
>Can someone tell me which pins to switch to make a serial cable into a
>null-modem cable?  Then I can use it in my...
>[snip]...so, my plan is to write a simple program in C that will
>send the flow from the serial port to a file in my network
>directory...then I can go across campus to the fast machine with the SVGA
>monitor and do some computer art!

If you're going to be transferring graphics files big enough that they won't
fit on a floppy, you don't want to transfer them over a serial line.  Instead,
use a *parallel* null-modem cable (pinouts follow).  The program you need is
already written; it's called Interlnk.exe, and it comes with MS-DOS now.
Parallel port pinout (from Que's Upgrading and Repairing PC's, 3rd ed, p. 1128)
  1   -Strobe             Out
  2   +Data Bit 0         Out
  3   +Data Bit 1         Out
  4   +Data Bit 2         Out
  5   +Data Bit 3         Out
  6   +Data Bit 4         Out
  7   +Data Bit 5         Out
  8   +Data Bit 6         Out
  9   +Data Bit 7         Out
  10  -Acknowledge        In
  11  +Busy               In
  12  +Paper End          In
  13  +Select             In
  14  -Auto Feed          Out
  15  -Error              In
  16  -Initialize Printer Out
  17  -Select Input       Out
  18  -Data Bit 0 Return  In
  19  -Data Bit 1 Return  In
  20  -Data Bit 2 Return  In
  21  -Data Bit 3 Return  In
  22  -Data Bit 4 Return  In
  23  -Data Bit 5 Return  In
  24  -Data Bit 6 Return  In
  25  -Data Bit 7 Return  In

For testing parallel ports, you can make a loopback plug as follows:
  1 to 13
  2 to 15
  10 to 16
  11 to 17
  12 to 14

A commercial parallel null-modem cable has this wiring:  (it was $15, btw)
  1 to 1
  2 to 15
  3 to 13
  4 to 12
  5 to 10
  6 to 11
  7 n/c
  8 n/c
  9 n/c
  10 to 5
  11 to 6
  12 to 4
  13 to 3
  14 to 14
  15 to 2
  16 to 16
  17 to 17
  18-24 n/c
  25 to 25

ObHack:  One of our professors managed to trash the first sector of his hard
disk, so it could neither boot nor access the FAT.  Had he backed up?  Of
course not.  In order to recover his valuable information, I found a similar
computer (in the next office; hooray for standardization) and printed out a
copy of the first sector in hex.  Then, using Norton's DiskEdit, I typed the
information onto the first sector of the trashed hard disk, saved it, and
presto^H^H^H^H^H^H viola! (tm)  His hard disk was as good as new.

Child Child Child Child

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