Bottom line - I wouldn't recommend it, because there are too many things that could go wrong, even if the 6L speaker sounded great, which it doesn't. You'd be better off installing a Doorbell Fon, Viking, or something similar, to allow them to answer the door using the telephones.
+1
We use Tele-door and use the relay from the module into the Processors IO. Once the IO goes high PIP on the AMS appears with the camera showing and the door station rings through the phoneline. We also use door strikes so if the owner knows who is at the door they don't have to get up to let them in they just have to press the "door open" button on the TP. Works like a charm!
One note if using the Tele-door system. Only use the Audio door stations and install cameras for video as the door station cameras are horrible and don't allow for any manipulation.
