This Crestron CEN - CI3 - 3 Card Interface comes with three C3COM - 3 Cards installed. It's important to note that it does not include a power supply. This setup provides a great solution for specific interface needs without the added power supply component.

To use this Crestron CEN - CI3 - 3 Card Interface, first make sure you have a separate power supply as it doesn't come with one. Install the three C3COM - 3 cards that are already included. Connect it to your relevant system according to the basic connection rules. When handling, be gentle to avoid any damage to the cards. As for maintenance, keep it in a clean and dry place. Regularly check the connections to ensure they are secure. If you notice any issues, consult a professional for help.