Some level of integration for my GDX5 intercom system

I want to smarten up my doorbell/intercom. The main problem is that its very quiet so often with noise cancellation earphones we don’t hear it. Ideally an off the shelf solution would be ideal by its not supported by Ring and the Nuki system looks like hot garbage.

Any ideas on how I might integrate this into home assistant? I am wondering if there is any way to get ESP Home to listen for a series of tones to trigger home assistant.

More info on the GDX 4 wire intercom: GDX5 (4 Wire System) with Ring Intercom