It seems that there is still some confusion about the correct
pinouts to connect an HP 3000 port to a terminal.  You do _not_
want to cross pins 2 and 3.  The correct wiring for a db-25
to db-25 connection is:
 
             Pin 2 <----> Pin 2
  HP 3000    Pin 3 <----> Pin 3   Terminal
             Pin 7 <----> Pin 7
 
HP 3000 ports are configured as Data Communications Equipment
(DCE).  DCE's, such as modems, transmit on pin 3 (the way I
remember this is "HP 3000's transmit on pin 3") and receive
on pin 2.  Data Terminal Equipment, such as terminals, transmit
on pin 2 and receive on pin 3.  Straight-through wiring is
required so that the HP 3000 and the terminal are not trying
to transmit on the same wire and listen on the same wire.
 
Note that this three pin configuration will only work if the
HP 3000 port is defined as a terminal port.  If the port is
defined as a modem port, the HP 3000 expects to see voltage
on pins 4 (Request to Send (RTS)) and 20 (Data Terminal Ready
(DTR)).  HP terminals in general hold RTS and DTR high for
free.  If your HP 3000 port is defined as a modem port, then
at a minimum, you need:
 
             Pin 2  <----> Pin 2
  HP 3000    Pin 3  <----> Pin 3   Terminal
             Pin 4  <----> Pin 4
             Pin 7  <----> Pin 7
             Pin 20 <----> Pin 20
 
If your HP 3000 port is a three-pin ATP port then your pinout
should be:
 
            Pin 1  <----> Pin 7
  HP 3000   Pin 2  <----> Pin 2  Terminal
            Pin 3  <----> Pin 3
 
 
Leighton Nakata
Telamon, Inc.
[log in to unmask]