[asterisk-users] Panasonic Door phone monitor to Asterisk box?

[Steve Prior]

I'm considering getting a Panasonic video door phone system (VL-GM301A) 
which can interface with a PBX and would like to connect it to my 
Asterisk box with an analog FXS port.  Of course the Panasonic 
documentation only talks about hooking it up to a Panasonic PBX which 
only talks about using Panasonic phones, so it's hard to tell whether 
the 2 wire connection from the door phone monitor is analog or digital. 
  The video door phone itself hooks to the door phone monitor with a 2 
conductor wire, so that part is clearly digital since video, audio, and 
button press all go through that wire, but since the door phone central 
station apparently plugs into a Panasonic PBX FXS port which possibly 
supports fax machines I'm thinking that this might be an ordinary analog 
connection.

Does anyone know if the door phone interface is analog or digital? 
Anyone have experience with interfacing with one?

Thanks
Steve