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Troubleshooting RealPort in AIX


Check RealPort Profile:

All ports used with the RealPort driver require the RealPort profile setting on the ports in order to respond reliably. To configure the appropriate profile use the following commands on the Portserver/Digi One product(s): 

set port dev=rp range=*

Reboot the unit for the change to take effect:

boot action=reset

Check for carrier detect:

All tty and lp devices are modem devices. They require DCD in order to respond. The preferrence is to wire DCD from the device to the port. If DCD is not asserted check to see if the device is powered on and online. Check the LEDs on the port.

If an 8 pin RJ45 cable is being used and DSR is asserted but not DCD, use the following command on the Portserver:

set flow altpin=on ra=*

If DCD is not wired then force carrier must be enabled. This can be set in 

smit tty --> change/show characteristics --> tty## --> force carrier --> enable

LP devices are supposed to ignore carrier but I have seen systems that do require DCD. To force carrier, use the following command in AIX:
 chdev -l lp## -a forcedcd=enable

The chdev command only needs to be issued once.

Alternately, put the following command in an appropriate startup script
/usr/lbin/tty/stty-digi forcedcd /dev/lp##

the stty-digi command needs to be issued at each system boot.


Make sure that the PS is configured correctly.

set config

Check IP address, Submask, Gateway, Myname, and Nameserv.
The first three must be correct, the second two must be correct if you are using DNS services.
Review the port settings:

  • set port ra=* 
    • Any port that is going to have a RealPort device attached, should have:
    • dev=host auto=off bin=off dest= (Portserver)
    • dev=host auto=off bin=off dest= (Portserver II)
  •  set flow ra=*
    • Any port that is going to have a RealPort device attached, should have
    • all signals off except ixon and ixoff (which can be on or off)
    • and altpin (which should be off for a 10 wire cable and on for anything else).
  • set auth
    • will show settings like the following:
      Ind IPaddr          Mask            RealPort  Login   Unrestricted
      1         oooo-ooo -------- oooooooo
             	                            o-oooooo -------- oooooooo
    • Realport should show "o" for all RealPort ports. NB: The ports number across in groups of eight -- In the example above, all ports are set correctly except ports 5 and 10 (which are possibly being used for non-RealPort connections).
Check for stuck processes:

  • On the portserver, type:
  • If a proccess (RealPort or otherwise) is running on the port, type:
    kill tty=[port#] 
  • or unplug the serial device and reboot the PS.


  • Check the LEDs on the port to see if OFC is on. If so, try typing control-Q from a terminal attached to the port, or from the portserver, type:
    kill tty=[port#]

Make sure that the AIX host can reach the ports on the PS

Once who shows no processes on the port, from the AIX server, type:
	telnet [PS ip] [2000+port number] 

	{i.e. 2001 for port 1, 2016 for port 16} 

If the host cannot telnet to the port then RealPort will not connect to it. Double check the previous set commands on the PS.


Check that the RealPort sa is pointing to the correct PS

From AIX, type:
	smit dev --> Digi Portservers --> Change show --> sa##

There are entries for IP address and node name. Use only one or the other, not both. Make sure that it is the correct IP address or node name for the particular PS. If using the node name, make sure that the host can ping or telnet to that node name. (ping nodename)


Check the status of the RealPort daemon

From AIX, type:
	ps -ef | grep ncx

Note the time that the daemon started. Check again several minutes later. If the time has changed then the daemon attempted to connect to the PS, failed and tried again.

Reasons why the daemon will fail to connect and ways to reconnect If RealPort preceives that a devices is busy, it can keep it from reconnecting to the PS. A device is considered busy if a print queue has print jobs in it, or a non-getty login proccess such as Pick is used on a tty.

A way to discover which tty or lp device is busy, from AIX, type:

rmdev -l sa## -R

Rmdev will not define a device if it is busy. Rmdev will error out and stop on the device that is busy. Stop or kill the process on the device then re-execute rmdev. Once rmdev has defined all tty and lp devices and the sa device, the RealPort daemon is removed.

To restart the daemon type:

mkdev -l sa## 

The sa will become available and the tty and lp devices will become available. The print queue or login process may need to be restarted.
Last updated: Jun 25, 2019

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