The IN502, VGA Input Board Assembly is a Series 500 input board compatible with all Series 500 enclosures, such as the PS550. This board is sold seperately or part of a complete system. Installation is quick and painless. UNPLUG THE POWER CORD ATTACHED TO THE ENCLOSURE. Simply remove the single mounting screw that holds the IN500 Future Expansion Plate or other card where you plan to install the IN502. After removing the old plate, insert the new IN502 assembly. Replace the screw and reattach the power cord. The system automatically recognizes the new board installed so no further activity is required. However, in some cases, it may be necessary to adjust the audio trim to level the input amplitude to a nominal level. See the Installation Manual for more details regarding audio adjustments.