This Studer card (Part Number: A949.0427) offers four analog microphone/line inputs, ideal for your D21m system.

To use this Studer card, first make sure your D21m Modular I/O System is powered off. Then, carefully insert the card into the appropriate slot. Once it's in place, you can connect your microphones or line - level devices to the four analog inputs. When the system is powered on, you'll be able to start using it. Remember to handle the card gently to avoid any damage. For maintenance, keep the card in a clean and dry environment. Periodically check the connections to ensure they are secure. If you notice any issues, such as a loss of audio, first check the connections and then consult the Studer support team.