Dr Vipoir Vs The dreaded Gremlins

Episode 1 "The case of the missing serial port"

Gremlins delight in sabotaging Openlab systems.

One of their favorite past-times is messing with serial devices.

Say for instance that your start Openlab and find that you can no longer control your microscope or filterwheel because the pallet is missing.

If this is so then you’ve probably had a visit from a Gremlin.

Number one they may have just turned off the serial device in question, always make sure the device to be controlled is turned on.

Check the power LED on the front of the device.

If it doesn’t have one of these see if you can hear the cooling fan and check the mains cable.

Their old classic trick is to unplug the serial device from the keyspan adapter.

You’ll find that if you have a newer Mac i.e. a G4 you will probably have a Keyspan Adapter plugged into one of the available USB ports.

Most Keyspan Adapters that we use have 2 circular serial ports for plugging in serial devices.

However there are other variations available take a look at the full product range at the following site:-


If you have lost control of a device the first place to look is the cables.

The serial devices that Openlab supports will use an RS232 serial cable.

From the serial device follow the cable from the port labelled either RS232 or Serial I/O to the Keyspan Adapter.

Gremlins like to swap the serial cables around so they are plugged into the wrong ports on the Keyspan Adapter.

If you are ever in doubt as to which serial ports are being used its easy to check.

You need to allocate serial ports in Openlab so that the software knows what port to use to control a specific device.

If you go to the "Edit’ menu and select ""Preferences", you will see the following window.

For purposes of this demonstration Dr Vipoir has picked his personal favourite the Orbit.

Now it’s a case of which port to use.

As you can see there are 2 possibles.

The Printer port USB or the port named P≠2USA28X11.

The Printer Port USB is Keyspan port1 and the port named P≠2USA28X11 is port 2.

So all you need to do is allocate the correct port.

If someone has re-named the ports you can always double check them with the "Keyspan USA-28X Manager"

Go to the "Control Panels" and select "Keyspan USA28X Serial Assistant"

A click on the advanced settings button will take you into the manager.

See the figure below for details.

As you can see you can view the port name.

If at any time you force quit Openlab then restart the application, you will loose control of your serial devices.

This is due to the fact that the ports have not been closed down correctly and Openlab thinks that the ports are still in use.

Just before we part for another month:

If you are using an older Mac i.e. a beige G3 equipped with in-built modem and printer serial ports here is something to bear in mind.

If Appletalk is turned on and the computer cannot establish a connection with the in-built ethernet it will use one of the local ports instead.

This may prevent the use of a serial device with Openlab.

If the computer is not connected to a network please ensure that Appletalk is turned off.

This can easily be done via the control strip.

If you suspect that you’ve been the victim of a Gremlin attack please call the support desk.

EU +44 (0) 247669 8121




(781) 402 0211