We are in the process of developing a carpark controller which are located next to the actual barrier. We wish to include an Intercom which allows communication to the management office. To add a microphone seems next to impossible unless one uses a USB Audio Adapter like this one:
As for the speaker (Visaton K 40 - 8 Ohm)
would it be best to connect it also to the USB Audio Adapter or directly to the Pi 2? If connecting a speaker directly to the Raspberry Pi 2 what should be the optimal impedance? The sound (speech only) should be heard 1-2 meter away (typical distance from driver of vehicle to intercom).