Audio Extension Board

This extension board adds full audio capability to your Doorman S3. It allows you to both listen and transmit audio back through the intercom bus.

The board is built around the ES8388 audio codec, providing high-quality analog-to-digital and digital-to-analog conversion for reliable two-way audio communication.

LIMITATIONS

The extension board connector on the Doorman core board was introduced in revision 2.0.0 and is unfortunately not available on earlier versions. A Doorman core board of revision 2.0.0 or later is required in order to connect extension boards.

Audio channels

The extension board provides two audio channels: the first handles intercom bus audio through the L1 and R1 inputs and L1 output, with L1 output also feeding directly into R1 input, which acts as a differential signal to filter the output and reduce noise. R1 output can also serve independently as a line-level output. The second channel offers L2 and R2 outputs for line-level audio and L2 and R2 inputs for additional line-level sources.

Assembly

Simply plug the extension board into the 2×7-pin connector on the Doorman core board. It's very easy — just follow the video guide below.