The cable link replaces the need to connect the command keyboard to an external computer by directly connecting the robot to the external computer and the power supply. The cable link also eliminates the need to equip the robot with batteries.
 2013 - Modulus Robots 

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The cable link is equipped with a user port plug for the Commodore 64/128 personal computers that can take control of the robot's movements through programming.

See the demo disk page for program examples for the cable link connection and the user manual page to see the connection pinouts.
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