Ref: 21770006
Title: How to Connect to an HP3000 Using TCP/LAT 4.0 Software
Date: 4/3/91

Copyright 3Com Corporation, 1991.  All rights reserved.

With the release of SW/TCP-LAT 4.0, you can no longer setd
dev=HewlettPackard.  This option, available on SW/TCP 3.2 and prior,
automatically set FlowControlFrom=enq_ack and FlowControlTo=none.  It
allowed the 3Com Communications Server to protect itself from data overrun
when attached to an HP3000 ATP or ADCC serial port using the proprietary
enq_ack flow control protocol.

If a 3Com Communications Server is connected to an ATP port on an
HP3000, you will normally need to set FlowControlFrom=enq_ack unless the
terminal type configured for the particular logical device that
corresponds to the ATP port does not implement it; for example, termtype 18
does not implement it.  This presents an obvious problem for customers using
TCP/LAT 4.0 software.

However, even if there is no FlowControlFrom=enq_ack setting on TCP/LAT 4.0,
it is still possible to communicate with the HP3000 ATP port by making a
copy of and then modifying the termtype file on the HP3000.  For example,
if the ATP port is configured with termtype 10, the HP System Administrator
would run the program TTUTIL.PUB.SYS and modify TT10.PUB.SYS (termtype 10)
to remove the escape sequences that set up enq_ack flow control.  This
is not as easy as issuing a setd dev = hp on a 3Com Communication Server, but
it is a solution that can be implemented when using TCP/LAT 4.0 software.
The System Administrator must reconfigure the ATP port and reboot the HP3000
to enable the configuration changes.
