Question:  Have successfully added different 2-way VHF audio sources on a remote IP V-Series panel using the External 1 and 2 inputs on the Auxiliary Audio connector. Audio form the remote IP panel (mic and VHF radio ) is heard on one of the panels in our Flight Control Room. I am able to adjust the relative levels between the VHF radio and the IP panel mic using the AudioMixer on the IP V-Series panel.
The question is …. At the when listening at my panel to the audio from the remote IP panel (Mic + VHF radio) in the main control room. I am not able to turn off the audio (of the VHF radio) when when the remote IP panel stops speaking  The panel mic itself can be turned off but the Ext Audio continues (VHF radio). Am I over looking something? 
Answer:  When using the V-Series DSP Audio mixer. The audio from External 1 and 2 auxiliary input is set as crosspoint in the DSP audio mixer to the desired destination on the V-panel (speaker, HS-1 or HS- 2 and matrix #1).  When the EXT-1 input is routed to the matrix #1 output (via the DSP audio mixer) then any audio from Ext 1 is sent to the matrix even if the Remote panel is not actively speaking. 
Iff you need to disable this audio then you need to inhibit all audio from the Remote panel being routed to any other port / panel on the system. This can be done using the ECS route command Go to ECS  > routes and create a route (from the source to destination), <from Remote IP panel to Panel in the Control room) Selecting "Inhibit" as the route action and Go to ECS > Controls > create a new control and attach the route you just made to the control Go to ECS > Panel programming and place the control label on to a key on the panel in the main control room When the "control-key" is activated the all audio from the Remote panel (Mic + VHF radio via the External 1 input) will be disabled.