Non Captive Linear Actuator - How to hook it up??

Hi

I bought a Non Captive Linear stepper motor from here

http://www.motioncontrolproducts.co.uk/product_info.php?cPath=1030&products_id=62

http://www.motioncontrolproducts.co.uk/pdf/PMlinearstepper-25%20(2).pdf

its the 25NCLA-B04, I thought it was just a standard stepper motor, but this connection has 6 cables from it being

Yellow Orange Red Black Brown White

All the wiring examples I've seen online only have 5 cables for the stepper motors... am I missing something?

Thanks in advance for any help, greatfully recieved!

http://www.arduino.cc/en/Tutorial/StepperUnipolar