Re: RS6000 RS-232 Console - Beware

[Jim . Rees]

  DTR is one of those control signals that should float asserted, so
  removing the plug should let output go through - and get lost.

Not true.  All rs-232 signals float to 0 volts, which is undefined.  They
have to be actively pulled to at least plus or minus 5 volts or you don't
have a valid signal.