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From: flash@lehi3b15.csee.Lehigh.EDU (Stephen Corbesero)
Newsgroups: comp.sys.att,comp.terminals
Subject: AT&T MTG-630 Terminals, Ethernet, Flow Control
Message-ID: <622@lehi3b15.csee.Lehigh.EDU>
Date: 22 Sep 89 18:48:17 GMT
Followup-To: comp.sys.att
Organization: CSEE Dept. Lehigh University, Bethlehem, PA
Lines: 28


I have 12 of the AT&T Multi-Tasking Graphic terminals (MTG-630) hooked
up serially to ethernet terminal servers (Bridge/3Com CS/210) and I
have two distinct problems.

1) I have already discovered and verified with AT&T that the layers
   environment will not run across an ethernet link.  They have no
   plans to fix this problem.

2) The terminals do need some sort of flow control.  XON/XOFF to the
   terminal server works fine, but giving up ^S and ^Q is just not
   feasible.  The terminal manual lists RS-232 pins 4 & 5 (RTS & CTS),
   and the terminal server documents it as a supported method, but
   apparently the terminals do not use them.

With respect to the first problem, I will be trying to get the
"stand-alone" graphics routines to run in a single-tasking mode.  If
someone has already worked around this problem, perhaps by
rewriting the the sxt drivers, I'd appreciate any information.

With respect to the second problem, I have found a set of LF and CR
delays values that seem togive the terminal enough to time in both
line-oriented mode and screen-oriented modes.  I regard this as a
kludge, and I would prefer a better solution.  I am really stunned
that such a powerful terminal (with 2 MB of memory!) requires flow
control, and that there is apparently no hardware flow control.  Any
information or experience in this area would also be greatly
appreciated.