Color QC and Matching Blog

Connecting your color spectrophotometer to OnColor with a USB adapter

Posted by Tom Merck on Wed, Sep 02, 2009

Many color instruments and spectrophotometers in use today come with a serial cable to connect and communicate with a computer.  However, serial ports are a thing of the past and very few PC's come with a serial port as standard configuration these days.  While you can always install a serial port, an easier way to connect to the PC is to use a Serial to USB adapter.  This is a special cable that plugs into the serial port output of your spectrophotometer on one end and plugs into a USB port on the computer on the other.  This circumvents the need for a serial port on the PC. 

There are a few tricks to getting this to work however.   Resist the temptation to just plug the cable in and see if it works!!!    First, it is important that you read and follow the installation instructions that come with the USB adapter.  Typically (but not always), the instructions will direct you install a driver for the adapter BEFORE plugging it into the computer.  It's important that you follow the proper sequence, because once you get Windows confused on what is attached to this port, it can be difficult to undo it.

After installing the driver, go to the Windows Device Manager and go to Ports and note what COMM PORT the adapter was assigned to. I In Windows Xp Device Manager is found under Control Panel, then System, then Hardware tab, and then Device Manager button.) You will need to know this in OnColor when you tell it what Comm. Port to look for the spectro on.  Then connect the spectrophotometer to the adapter and finally plug it into the PC.   

For spectrophotometers that do not use a "straight through" cable, you will need to use the manufacturer's cable out of the spectro and then attach the USB adapter to the 9-pin end of that cable.  (Examples of spectros like this would include the Konica Minolta CM-3600d, CM-2600/2500d and CM-3700d.)  

Finally, you can open OnColor and go to Communications, choose the comm. Port assigned to this adapter and then test the settings.  You should be good to go.

Don't move the adapter around to different USB ports, as the driver typically only configures it for that one USB port.  If you move it to another USB port, it may be assigned to a different comm. Port number. 

Not all USB adapters are created equal.  Some are not compatible with Windows Vista.  Others don't handle this type of data communication well.  We recommend the Belkin serial to USB adapter ( )  since many OnColor users report no problems using this model.

Tags: OnColor, USB adapter, color spectrophotometer