[bit.listserv.pmdf-l] Reverse LAT problems

COLEVE@UVADM.UVCC.EDU (Vern Cole -- Systems Manager) (02/07/90)

Bob Boyd writes, in part:
>3.  I'm trying to use reverse LAT to go out of the VAX to a
>    terminal server port which is connected into a Gandalf dataswitch.
>    The problem seems to be that the PMDF routines don't get beyond the
>    first XMIT before MASTER dies -- see log file that I've included
>    below.  What am I missing?  I can use VAXNET and/or Kermit and
>    talk to this port just fine. What's different?
> [...]
>module name     routine name                     line       rel PC    abs PC
>                                                           0004204F  0004204F
>MASTER          DI_FATAL_ERROR                   1108      00000421  00004CAD
>OSMOD           OS_READCHAR                       721      00000114  0000F6D4
>MASTER          RECV                             3707      00000044  00008B48
>MASTER          DOSCRIPT                         3752      0000024A  0000898E
>MASTER          MASTER                           3785      000001A5  000077C5
> [...]
> The contents of the .TRN file is the first record of the x_SCRIPT
> xmit which should cause autobaud to be done and a prompt to come back.
>

I've quit using phone net, having now established a link to my routing
system using async decnet, but the problems you are having sound familiar.
I had no Pascal compiler when I was doing this so I could never find the
actual problem, but here is what I learned:

1) Don't trust the \x timer in a script.  It works sometimes and sometimes it
doesn't.  I have read the source code and can find nothing wrong.  It HAS to
work correctly... but it doesn't... always.

2) Don't trust the .TRN log file either.  Everything which actually happens
will be there, but a lot of stuff may be happening and not be there.  Use a
datascope on the line.  If you don't have a data scope, wire an RS232 "T"
connecting to pins seven and two or three on your Data Communications
Equipment.  You can use a terminal set for "display controls" to monitor
the line and learn a lot.

The "T":

Data Comm Equip. (modem)                      Data Terminal Equip. (VAX)
2-----------o--------------------------------------------------------<--2
3-->-----o--+-----------------------------------------------------------3
7-----o--+--+-----------------------------------------------------------7
8-->--+--+--+-----------------------------------------------------------8
20----+--+--+--------------------------------------------------------<-20
      |  |  |               DCE/DTE switch
      |  |  o----------------o  dce                   Ethnic data scope.
      |  |                  ======o----------------------------------3
      |  o-------------------o  dte
      |
      o--------------------------------------------------------------7

[[ "Ethnic" can be any group you personally despise.  Poles, Blacks,
Whites, Okies, Aggies, Utahns...]

3) (This one may not apply to reverse LAT, I used a straight VAX line.)
Use a breakout box to check the condition of DTE from the VAX.  If the
line has EVER been set to "/HANGUP" a counter will lower DTE every 20 seconds
unless CD is detected.  Setting the line /NOHANGUP will not undo this.
The time is just about right to establish a long distance call but not get
carrier yet.

Good luck.  (You'll need it.)
---------------------
Vern Cole -- Systems Manager -- Utah Valley Community College
snailmail: 800 W. 1200 South, Orem, UT 84058 USA
Voice: (801)222-8000 ext 160            Radio: KF7XM @ 145.37(-)mhz
Internet: COLEVE@UVADM.UVCC.EDU         Bitnet: VCOLE@UTAHCCA