It needs to be programmed using the Celestron Firmware Manager (CFM).
Please go to this link for the instructions:
http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=2584
Here is information on the USB-RS232 cable you need:
http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1698
Here is information on the other cable you need:
http://www.celestron.com/science_education/cable-nexstar-rs-232.html