Software Spybug -Listen to the room a SNOM VoIP linux tel is by appcode

Hello, I have a SNOM VoIP phone which runs with linux. In the internet it is written that it´s possible to use the phone as spybug and listen into a room where the phone is located. How can I do that?... (Budget: $30-$250 USD, Jobs: Linux, PHP, Shell Script, Software Architecture, VoIP)
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