I'm looking to use my Spark Core to control my door buzzer in my apartment. I'd like to identify the correct parts I need to build the required circuit, but this seems to be dependent on the voltage and current type that the buzzer system uses. I have been referencing this question: to try and identify the proper relay and transistor needed. Here is the schematic for my buzzer system (My apartment unit has model 3404 inside it with LISTEN, TALK, and DOOR buttons):
According to this similar example, I need to find a relay with a coil voltage equal to that of the door buzzer system. Also, as the Spark core provides 3.3 VDC, I believe I would need to amplify this using a transistor. From the schematic, can you help me identify what the voltage and type the system uses, and also what types of relay and transistor I would need for the circuit?