  Differences between LAT and TCP/IP? 
 The Question is:
 
In the manufacturing environment here, we have CNC machines hooked to LAT
ports on DECServers. The setup is reqd to transfer files between machine
tools and a node in the VAX network. The file tranfer software is a
home-grown program coded in FORTRAN. It
uses
SYS$QIOW function calls to set/read/write ports.
 
We are planning to move the current setup to TCP/IP compatible network by
replacing DEC terminal servers with hubs having RS232 serial ports to
connect machine tools.
 
I would like to know if the old LAT compatible file transfer program will
work in the new TCP/IP environment. We did some tests, and of course, they
failed. Can you give some pointers to the type of modifications that may be
required for the file transfer
 program to work with TCP/IP ?
 
 The Answer is:
 
  LAT and TCP/IP are completely different protocols, with different
  implementations and different programming interfaces, and with not
  entirely consistent capabilities.
 
  Without details on what the current application is doing, details on what
  modifications will be required is difficult at best -- start by looking
  at what the current code is doing, and map it against what is possible
  via the socket or sys$qio[w] interface to the particular TCP/IP package
  expected, and what sort of communications (raw, telnet, etc) are planned.
