  Serial line wiring? (DECserver pinouts) 
 The Question is:
 
we are currently using DECserver 200s with null
modem cables hooked to proprietary devices. Both
are 25-pin RS232. We want to go to the 32 port
DECserver 900TM, but our preliminary tests are
failing. With the RJ45 8-wire jacks on the 900
do we still need to do the null modem cabling
or should we be trying straight through cabling?
 
Our wiring for the cables from the 200 ports to
our devices is a TRUE null modem cable.
 
Thanks in advance
 
 
 The Answer is:
 
  Please use a serial line breakout box or similar device, and determine
  exactly what signals are required in the current (working) configuration,
  and what signals and wiring you have access to in the new configuration.
 
  Often examination of the wiring tell you if you are working with a
  cross-over (null modem) cable, or one that is wired straight through.
  If visual examination fails, probing it with a multi-meter will work.
 
