What type of cable do I need to make a serial connection between my PC and HP9000 UNIX console?

  • 7021683
  • 13-Nov-2003
  • 01-Apr-2018


Reflection for HP version 13.0 through 14.x


This technical note describes the type of cable/adapter needed to make a serial connection from a computer running Reflection for HP to an HP9000 UNIX (HPUX) host.


The type of cable(s) needed to make a serial connection between a PC and an HPUX host depends on the types of ports you are connecting. Depending on the hardware installed on your PC and host, you may have one or more of the following options:
Possible Ports
Serial port
USB port

HPUX host
Console serial port
Console USB port
MUX (multiplexer)

Using a combination of cables, any of the PC port types listed above can be connected to any of the host port types noted. Regardless of which two types of ports you will be connecting, somewhere in the cabling you must use either of the following pieces of hardware:

  • An RS-232 null modem cable (also called an RS-232 cross-over cable), with the appropriate terminators.
  • A Null modem adapter somewhere in the cabling between the PC port and host port.

A null modem cable or adapter crosses the transmit data wire (pin 2) and receive data wire (pin 3).

For example, to make a direct serial connection from a PC's 9-pin serial port to a 9-pin serial port on the HPUX, you will need a 9-pin RS-232 null modem cable (also called an RS-232 cross-over cable).

Or, if you only have a standard (non-null modem) RS-232 modem cable, you must insert a null modem adapter to the end of the standard RS-232 cable (between the cable and either the console serial port on the host or the PC serial port) to reverse the cable's transmit and receive signals.


After connecting your PC and HPUX console using an RS-232 null modem cable or null modem adapter, if you are unable to make a serial connection to the host using Reflection for HP, verify the following.

  • In Reflection, verify that you have selected the correct serial port for your workstation in Connection > Connection Setup.
  • Make sure that the RS-232 cable you are using is a null modem cable. If you are unsure, insert a null modem adapter between the cable and your workstation port, and then try connecting again.

Additional Information

Legacy KB ID

This document was originally published as Attachmate Technical Note 1746.